NOTE 9 - COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax and regulatory proceedings before various courts, regulatory commissions, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in the notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.

Reference is made to Note 1 - Summary of Significant Accounting Policies, Note 2 - Rate and Regulatory Matters, Note 14 - Related Party Transactions, and Note 15 - Commitments and Contingencies under Part II, Item 8 of the Form 10-K. See also Note 1 - Summary of Significant Accounting Policies, Note 2 - Rate and Regulatory Matters, Note 8 - Related Party Transactions and Note 10 - Callaway Energy Center in this report.

Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri's Callaway energy center at June 30, 2011. The property coverage and the nuclear liability coverage must be renewed on April 1 and January 1, respectively, of each year.


Type and Source of Coverage	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	$	375		$	-
Pool participation		12,219	^(a)		118	^(b)
	$	12,594	^(c)	$	118
Property damage:
Nuclear Electric Insurance Ltd.	$	2,750	^(d)	$	23
Replacement power:
Nuclear Electric Insurance Ltd.	$	490	^(e)	$	9
Energy Risk Assurance Company	$	64	^(f)	$	-

(a)	Provided through mandatory participation in an industry-wide retrospective premium assessment program.

(b)	Retrospective premium under Price-Anderson. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed U.S. commercial reactor, payable at $17.5 million per year.

(c)

Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $118 million per incident for each licensed reactor it operates with a maximum of $17.5 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

(d)	Provides for $500 million in property damage and decontamination, excess property insurance, and premature decommissioning coverage up to $2.25 billion for losses in excess of the $500 million primary coverage.

(e)

Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first eight weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million.

(f)

Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. The coverage commences after the first 52 weeks of insurance coverage from Nuclear Electric Insurance Ltd. and is for a weekly indemnity of $900,000 for 71 weeks in excess of the $3.6 million per week set forth above. Energy Risk Assurance Company is an affiliate and has reinsured this coverage with third-party insurance companies. See Note 8 - Related Party Transactions for more information on this affiliate transaction.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear power facility. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The five-year inflationary adjustment as prescribed by the most recent Price-Anderson Act renewal was effective October 29, 2008. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by Price-Anderson.

Losses resulting from terrorist attacks are covered under Nuclear Electric Insurance Ltd.'s policies, subject to an industry-wide aggregate policy limit of $3.24 billion within a 12-month period for coverage for such terrorist acts.

If losses from a nuclear incident at the Callaway energy center exceed the limits of, or are not covered by, insurance, or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren's and Ameren Missouri's results of operations, financial position, or liquidity.

Other Obligations

To supply a portion of the fuel requirements of our energy centers, we have entered into various long-term commitments for the procurement of coal, natural gas and nuclear fuel. We have also entered into various long-term commitments for the purchase of electric capacity and natural gas for distribution. For a complete listing of our obligations and commitments, see Note 15 - Commitments and Contingencies under Part II, Item 8, of the Form 10-K.

Our commitments for the procurement of coal have materially increased from the amounts previously disclosed in the Form 10-K. In July 2011, Ameren Missouri entered into multi-year agreements to procure ultra low-sulfur coal and the related transportation, from the Powder River Basin in Wyoming. The following table presents our total estimated coal procurement and related transportation commitments at July 19, 2011, including the July 2011 ultra low-sulfur coal and the related transportation agreements:


	2011		2012		2013		2014		2015		Thereafter
Ameren	$	669	$	1,153	$	801	$	643	$	634	$	1,651
Ameren Missouri		244		618		609		630		620		1,589

Ameren's and Ameren Illinois' commitments for the procurement of purchased power have materially changed due to the 2011 RFP process administered by the IPA in the second quarter from amounts previously disclosed in Form 10-K as of December 31, 2010. See also Note 8 - Related Party Transactions in this report. The following table presents our total estimated purchased power commitments at June 30, 2011:


	2011		2012		2013		2014		2015		Thereafter
Ameren	$	178	$	200	$	314	$	129	$	55	$	826
Ameren Illinois		165		177		290		106		32		624

Environmental Matters

We are subject to various environmental laws and regulations enforced by federal, state and local authorities. From the beginning phases of siting and development to the ongoing operation of existing or new electric generating, transmission and distribution facilities, natural gas storage facilities, and natural gas transmission and distribution facilities, our activities involve compliance with diverse environmental laws and regulations. These laws and regulations address emissions, impacts to air, land and water, noise, protected natural and cultural resources (such as wetlands, endangered species and other protected wildlife, and archeological and historical resources), and chemical and waste handling. Complex and lengthy processes are required to obtain approvals, permits, or licenses for new, existing or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials (including wastes) requires release prevention plans and emergency response procedures.

In addition to existing laws and regulations governing our facilities, the EPA is developing numerous new environmental regulations that will have a significant impact on the electric utility industry. These regulations could be particularly burdensome for certain companies, including Ameren, Ameren Missouri and Genco, that operate coal-fired energy centers. Significant new rules already proposed or promulgated since the beginning of 2010 include the regulation of greenhouse gas emissions; revised ambient air quality standards for SO₂ and NO₂ emissions increasing the stringency of the existing ozone national ambient air quality standard; the CSAPR, which will require further reduction of SO₂ and NO_x emissions from power plants; a regulation governing management of CCR and coal ash impoundments; MACT standards for the control of hazardous air pollutants, such as mercury, metals, and acid gases from power plants; revised NSPS for particulate matter, SO₂ and NO_x emissions from new sources; and new regulations under the Clean Water Act, that could require significant capital expenditures such as new water intake structures or cooling towers at our energy centers. Within the next year, the EPA is also expected to propose NSPS and emission guidelines for greenhouse gas emissions applicable to new and existing electric generating units as well as further reductions in the annual national ambient air quality standards for ozone and fine particulates. The EPA also plans to propose an additional rule governing air pollutant transport, but has not specified when it will issue that proposal. These new regulations may be challenged with lawsuits, so the timing of their ultimate implementation is uncertain. Although many details of these future regulations are unknown, the combined effects of the new and proposed environmental regulations may result in significant capital expenditures and/or increased operating costs over the next five to ten years for Ameren, Ameren Missouri and Genco. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. As a result, these regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of plant assets. Failure to comply with environmental laws and regulations may also result in the imposition of fines, penalties, and injunctive measures.

The estimates in the table below contain all of the known capital costs to comply with existing environmental regulations and our preliminary assessment of the potential impacts of the EPA's proposed regulation for CCR, the proposed MACT standard for the control of mercury and other hazardous air pollutants, the finalized CSAPR, and the revised national ambient air quality standards for SO₂ and NO₂ emissions as of June 30, 2011. The estimates in the table below assume that CCR will continue to be regarded as nonhazardous. The estimates in the table below do not include the impacts of new regulations proposed by the EPA under the Clean Water Act in March 2011 regarding cooling water intake structures as our evaluation of those impacts is ongoing. The estimates shown in the table below could change significantly depending upon additional federal or state requirements, regulation of greenhouse gas emissions, new hourly national ambient air quality standards or changes to existing standards for SO₂ and NO₂ emissions, the final requirements under a MACT standard for the control of hazardous air pollutants such as mercury, metals, and acid gases, additional rules governing air pollutant transport, finalized regulations under the Clean Water Act, CCR being classified as hazardous, our finalized CSAPR compliance plans, new technology, variations in costs of material or labor, or alternative compliance strategies, among other factors. Ameren Missouri's estimate in the table below includes the impacts of its July 2011 multi-year agreement, to procure ultra low-sulfur coal. This change in fuel mix is estimated to eliminate or postpone past 2020, $1.1 billion of Ameren Missouri's capital expenditures for pollution control equipment compared with the estimated capital expenditures included in the Form 10-K. In addition, the estimates for Genco and AERG in the table below have been updated from the estimates provided in the Form 10-K, based on the Merchant Generation segment's continued optimization of environmental compliance plans.


	2011		2012 - 2015					2016 - 2020					Total
AMO^(a)	$	40	$	315	-	$	390	$	905	-	$	1,105	$	1,260	-	$	1,535
Genco		125		355	-		435		60	-		75		540	-		635
AERG		10		170	-		210		10	-		15		190	-		235
Ameren	$	175	$	840	-	$	1,035	$	975	-	$	1,195	$	1,990	-	$	2,405

(a)	Ameren Missouri's expenditures are expected to be recoverable from ratepayers.

The following sections describe the more significant environmental rules that affect our operations.

Clean Air Act

Both federal and state laws require significant reductions in SO₂and NO_x emissions that result from burning fossil fuels. In March 2005, the EPA issued regulations with respect to SO₂ and NO_x emissions (the CAIR). The CAIR required generating facilities in 28 states, including Missouri and Illinois, and the District of Columbia to participate in cap-and-trade programs to reduce annual SO₂emissions, annual NO_x emissions, and ozone season NO_x emissions. The cap-and-trade program for both annual and ozone season NO_x emissions went into effect on January 1, 2009. The SO₂emissions cap-and-trade program went into effect on January 1, 2010.

In December 2008, the United States Court of Appeals for the District of Columbia remanded the CAIR to the EPA for further action to remedy the rule's flaws, but allowed the CAIR's cap-and-trade programs to remain effective until they are replaced by the EPA. In July 2011, the EPA issued the CSAPR as the CAIR replacement. The CSAPR, which becomes effective on January 1, 2012, for SO₂ and annual NO_x reductions and on May 1, 2012, for ozone season NO_xreductions, replaces CAIR and its applicable state rules. In the CSAPR, the EPA developed federal implementation plans for each state covered by this rule; however, each impacted state can develop its own implementation rule starting as early as 2013. The CSAPR establishes emission allowance budgets for each of the 23 states subject to the regulation, including Missouri and Illinois. With the CSAPR, the EPA abandoned CAIR's regional approach to cutting emissions and instead set a pollution budget for each of the impacted states based on the EPA's analysis of each upwind state's contribution to air quality in downwind states. For Missouri and Illinois, emission reductions are required in two phases beginning in 2012, with further reductions in 2014. The EPA estimates that by 2014, the CSAPR and other state and EPA actions will reduce SO₂ emissions from power plants by 73% and NO_x emissions by 54% from 2005 levels. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, either the SO₂, annual NO_x, or ozone season NO_xprogram. The CSAPR is voluminous and complex and our review of the finalized regulation and its impacts is ongoing. We cannot estimate at this time whether compliance with this rule will be prohibitively expensive for any of our coal-fired energy centers or if compliance with this rule will impact the expected useful lives of our coal-fired energy centers. Changes in useful life or operating cost assumptions could result in future asset impairments. Genco's Hutsonville and Meredosia energy centers, and a unit, specifically unit one, at AERG's E.D. Edwards energy center, are the Merchant Generation segment's least economic coal-fired facilities and the most exposed for future asset impairments. Genco's net investment in its Hutsonville and Meredosia energy centers totaled approximately $26 million and $1 million, respectively, and AERG's net investment in unit one at the E.D. Edwards energy center totaled $18 million as of June 30, 2011.

Separately, in January and June 2010, the EPA finalized new ambient air quality standards for SO₂ and NO₂ and also announced plans for further reductions in the annual national ambient air quality standards for ozone and fine particulates. The state of Illinois and the state of Missouri will be required to individually develop attainment plans to comply with the new ambient air quality standards. Ameren, Ameren Missouri and Genco continue to assess the impacts of these new standards. In July 2011, the EPA announced it is delaying the issuance of new annual national ambient air quality standards for ozone and fine particulates.

In March 2011, the EPA issued proposed rules under the Clean Air Act that establish a MACT standard to control mercury emissions and other hazardous air pollutants, such as acid gases, metals, and particulate matter. The MACT standard sets emission limits equal to the average emissions of the best performing 12% of existing coal and oil-fired electric generating units. The EPA estimates that the new rule would result in a 91% reduction in mercury emissions from coal-fired power plants. Also, the proposed rule requires reductions in hydrogen chloride emissions, which were not regulated previously, and may require continuous monitoring systems that are currently not in place. The MACT standard does not require a specific control technology to achieve the emission reductions. However, potentially applicable control technologies discussed in the proposed rule include scrubbers, dry sorbent injection, selective catalytic reduction, electrostatic precipitators, activated carbon injection and fabric filters. The MACT standard will apply to each unit at a coal-fired power plant; however, in certain circumstances, emission compliance can be averaged for the entire power plant. The EPA also proposed to revise the NSPS applicable to particulate matter, SO₂and NO_x.The proposed rules are scheduled to be finalized in November 2011. Compliance is expected to be required no later than 2016 and potentially as early as late 2014. This new proposed rule is voluminous and complex, with final rules likely to be different. Ameren's review of its impact is ongoing. We cannot at this time predict whether compliance with this rule, when finalized, would be prohibitively expensive for any of our coal-fired energy centers or if compliance with this proposed rule would impact the expected useful lives of our energy centers. Changes in useful life or operating cost assumptions could result in future asset impairments.

Ameren Missouri's current environmental compliance plan for air emissions from its energy centers includes burning more ultra low-sulfur coal and installing additional pollution control equipment. The July 2011 purchase contract, as discussed in Other Obligations above, to procure significant volumes of lower sulfur-content coal than Ameren Missouri's energy centers currently burn will allow Ameren Missouri to eliminate or postpone capital expenditures for pollution control equipment while still achieving required emissions levels. In 2010, Ameren Missouri completed the installation of two scrubbers at its Sioux energy center to reduce SO₂ emissions. Currently, Ameren Missouri's compliance plan assumes the installation of two scrubbers within its coal-fired fleet during the next ten years and precipitator upgrades at multiple energy centers. However, Ameren Missouri is currently evaluating its operations and options to determine how to comply with the emissions requirements set forth in the finalized CSAPR, the proposed MACT standard for mercury and other hazardous air pollutants, and other recently finalized or proposed EPA regulations.

Similarly, Ameren and Genco are currently evaluating the EPA's finalized CSAPR and proposed MACT standard to control mercury and other hazardous air pollutants to determine whether the new federal rules and timeline are more stringent than the existing state regulations. That review is ongoing and could require a change in the compliance plan described below. Existing Illinois state regulations already required Ameren and Genco to reduce their emissions of mercury under the MPS. Based on Ameren's and Genco's preliminary review of the proposed MACT standard, the scope of the federal standard is broader than the MPS as no exemption exists for smaller coal-fired plants. Additionally, the proposed federal rule appears more stringent than the MPS because it does not authorize compliance demonstrations based on a 12-month rolling average emission calculation as authorized under the MPS.

Under the MPS, as amended, Illinois generators are required to reduce mercury, SO₂, and NO_x emissions by 2015. To comply with the MPS, Genco and AERG are installing equipment designed to reduce mercury, NO_x, and SO₂ emissions. Genco and AERG have installed a total of three scrubbers at two energy centers and preparations for the construction of two additional scrubbers are underway at a third energy center, with completion expected in late 2013 and spring 2014. Currently, Genco's and AERG's compliance strategies and resulting estimated environmental capital expenditures also include precipitator upgrades at Genco's Joppa energy center and the inclusion of baghouse and dry sorbent injection SO₂ reduction technology at AERG's E.D. Edwards energy center. Genco and AERG may also need to install additional, or optimize existing pollution control equipment to meet new emission reduction requirements under the MPS, CSAPR, or the proposed federal MACT standard as they become effective.

The completion of Ameren's, Ameren Missouri's and Genco's review of recently finalized or proposed environmental regulations and compliance measures could result in significant increases in capital expenditures and operating costs. The compliance costs could be prohibitive at some of our energy centers as the expected return from these investments might not justify the required capital expenditures or their continued operation, which could result in the impairment of plant assets.

Emission Allowances

The Clean Air Act created marketable commodities called allowances under the acid rain program, the NO_x budget trading program, the federal CAIR, and beginning in 2012, the CSAPR. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, either the SO₂, annual NO_x, or ozone season NO_xprograms. See Note 1 - Summary of Significant Accounting Policies for the SO₂ and NO_x emission allowance book values that were classified as intangible assets as of June 30, 2011, and the impairment recorded during the three and six months ended June 30, 2011.

Environmental regulations, including the CAIR and CSAPR, the timing of the installation of pollution control equipment, fuel mix, and the level of operations, will have a significant impact on the number of allowances required for ongoing operations. The CAIR, effective until the end of 2011, uses the acid rain program's allowances for SO₂emissions and the NO_x budget trading program for both the annual and ozone season NO_x allowances. The CSAPR, the CAIR replacement, however, will not rely upon the acid rain program, the NO_x budget trading program, or CAIR allowances for its allowance allocation program. Instead, the EPA will issue a new type of emissions allowance for each program under the CSAPR. As a result, existing SO₂allowances may be used solely for achieving compliance with the acid rain program's SO₂ emission limitations. Consequently, Ameren, Ameren Missouri and Genco do not expect to use all of their existing SO₂allowances for their operations. Any unused annual and ozone season NO_x allowances issued under CAIR cannot be used for compliance with CSAPR. Ameren, Ameren Missouri and Genco are analyzing the CSAPR's SO₂and NO_x emission allowance allocations and trading restrictions.

Based on a preliminary review of the emission allowances granted under the CSAPR, Ameren, Ameren Missouri and Genco expect their 2012 allotment of allowances will exceed their emission levels for SO₂ _.In addition, Ameren Missouri expects its 2012 allotment of annual and ozone season NO_x emission allowances will exceed its emission levels. Conversely, the Merchant Generation segment's expected emissions for both annual and ozone season NO_x appear to exceed its 2012 allotment. Ameren, Ameren Missouri and Genco are studying their compliance options. Ameren, Ameren Missouri and Genco may be required to purchase emission allowances, if available, install new or optimize existing pollution control equipment, limit generation, or take other actions, including the potential closure of energy centers, to achieve compliance with the CSAPR.

Global Climate Change

Initiatives to limit greenhouse gas emissions and to address climate change have been subject to consideration in the U.S. Congress. Since 2009, legislation has been passed in the U.S. House of Representatives and proposed in the Senate to reduce greenhouse gas emissions from designated sources, including coal-fired electric generation units. Many of these proposals have included economy-wide cap-and-trade programs. The reduction of greenhouse gas emissions was identified as a high priority by President Obama's administration.

Potential impacts from any climate change legislation could vary, depending upon proposed CO₂ emission limits, the timing of implementation of those limits, the method of distributing any allowances, the degree to which offsets are allowed and available, and provisions for cost-containment measures, such as a "safety valve" provision that provides a maximum price for emission allowances. As a result of our diverse fuel portfolio, our emissions of greenhouse gases vary among our energy centers, but coal-fired power plants are significant sources of CO₂. Ameren's analysis shows that if most versions of recently proposed climate change bills were enacted into law, household costs and rates for electricity could rise significantly. The burden could fall particularly hard on electricity consumers and upon the economy in the Midwest because of the region's reliance on electricity generated by coal-fired power plants. Natural gas emits about half as much CO₂ as coal emits when burned to produce electricity. Therefore, climate change regulation could cause the conversion of coal-fired power plants to natural gas, or the construction of new natural gas plants to replace coal-fired power plants. As a result, economy-wide shifts to natural gas as a fuel source for electricity generation also could affect the cost of heating for our utility customers and many industrial processes that use natural gas. Higher costs for energy could contribute to reduced demand for electricity and natural gas.

In December 2009, the EPA issued its "endangerment finding" determining that greenhouse gas emissions, including CO₂, endanger human health and welfare and that emissions of greenhouse gases from motor vehicles contribute to that endangerment. In March 2010, the EPA issued a determination that greenhouse gas emissions from stationary sources, such as power plants, would be subject to regulation under the Clean Air Act in 2011. As a result of these actions, we are required to consider the emissions of greenhouse gases in any air permit application.

Recognizing the difficulties presented by regulating at once virtually all emitters of greenhouse gases, the EPA finalized in May 2010 regulations known as the "Tailoring Rule," that would establish new higher thresholds for regulating greenhouse gas emissions from stationary sources, such as power plants. The Tailoring Rule became effective in January 2011. The rule requires any source that already has an operating permit to have greenhouse gas-specific provisions added to its permits upon renewal. Currently, all Ameren energy centers have operating permits that, when renewed, may be modified to address greenhouse gas emissions. The Tailoring Rule also provides that if projects performed at major sources result in an increase in emissions of greenhouse gases of at least 75,000 tons per year, measured in CO₂ equivalents, such projects could trigger permitting requirements under the NSR/Prevention of Significant Deterioration program and the application of best available control technology, if any, to control greenhouse gas emissions. New major sources also would be required to obtain such a permit and to install the best available control technology if their greenhouse gas emissions exceed the applicable emissions threshold. Separately, in December 2010, the EPA announced it would establish NSPS for greenhouse gas emissions at new and existing fossil fuel-fired power plants. The EPA has extended its deadline to issue its proposed standard for power plants, called the performance standard, until the end of September 2011, with final standards expected in 2012. It is uncertain whether reductions to greenhouse gas emissions would be required at Ameren's, Ameren Missouri's or Genco's energy centers as a result of any of the EPA's new and future rules. Legal challenges to the EPA's greenhouse gas rules have been filed. Any federal climate change legislation that is enacted may preempt the EPA's regulation of greenhouse gas emissions, including the Tailoring Rule, particularly as it relates to power plant greenhouse gas emissions. The extent to which the Tailoring Rule could have a material impact on our energy centers depends upon how state agencies apply the EPA's guidelines as to what constitutes the best available control technology for greenhouse gas emissions from power plants, whether physical changes or changes in operations subject to the rule occur at our energy centers, and whether federal legislation that preempts the rule is passed.

Although the EPA has stated its intention to regulate greenhouse gas emissions from stationary sources, such as power plants, congressional action could block or delay that effort. In 2011, legislation was introduced in both the United States House of Representatives and Senate that would block the EPA from regulating greenhouse gas emissions from power plants and other stationary sources under the Clean Air Act. Separate legislation has also been introduced in both the United States House of Representatives and Senate that would delay the EPA's ability to regulate greenhouse gas emissions from stationary sources for two years. Although neither of these bills has been passed into law, Congress continues to discuss limiting the EPA's ability to regulate greenhouse gases.

Future federal and state legislation or regulations that mandate limits on the emission of greenhouse gases would likely result in significant increases in capital expenditures and operating costs, which, in turn, could lead to increased liquidity needs and higher financing costs. Moreover, to the extent Ameren Missouri requests recovery of these costs through rates, its regulators might deny some or all of, or defer timely recovery of, these costs. Excessive costs to comply with future legislation or regulations might force Ameren, Ameren Missouri and Genco as well as other similarly situated electric power generators to close some coal-fired facilities earlier than planned, which could lead to possible impairment of assets and reduced revenues. As a result, mandatory limits could have a material adverse impact on Ameren's, Ameren Missouri's, and Genco's results of operations, financial position, and liquidity.

Recent federal court decisions have considered the application of common law causes of action, such as nuisance, to address damages resulting from global climate change. In June 2011, the United States Supreme Court in State of Connecticut v. American Electric Power rejected state efforts to impose liability for CO₂ and greenhouse gases emissions under federal common law. That ruling, however, did not address whether private citizens could pursue causes of action based on state common law. In June 2011, litigation was filed in the United States District Court for the Southern District of Mississippi named Comer v. Murphy Oil (Comer), where a Mississippi property owner sued several industrial companies, including Ameren Missouri and Genco, alleging that CO₂ emissions created the atmospheric conditions that intensified Hurricane Katrina. While we are unable to predict the outcome of the Comer litigation on our results of operations, financial position, and liquidity, Ameren believes that it has meritorious defenses. Numerous procedural and substantive challenges are expected in the Comer litigation.

The impact on us of future initiatives related to greenhouse gas emissions and global climate change is unknown. Compliance costs could increase as future federal legislative, federal regulatory, and state-sponsored initiatives to control greenhouse gases continue to progress, making it more likely that some form of greenhouse gas emissions control will eventually be required. Since these initiatives continue to evolve, the impact on our coal-fired energy centers and our customers' costs is unknown, but any impact would probably be negative. Our costs of complying with any mandated federal or state greenhouse gas program could have a material impact on our future results of operations, financial position, and liquidity.

NSR and Clean Air Litigation

The EPA is engaged in an enforcement initiative to determine whether coal-fired power plants failed to comply with the requirements of the NSR and NSPS provisions under the Clean Air Act when the plants implemented modifications. The EPA's inquiries focus on whether projects performed at power plants should have triggered various permitting requirements and the installation of pollution control equipment.

In April 2005, Genco received a request from the EPA for information pursuant to Section 114(a) of the Clean Air Act. The request sought detailed operating and maintenance history data with respect to Genco's Coffeen, Hutsonville, Meredosia, Newton, and Joppa energy centers and AERG's E.D. Edwards and Duck Creek energy centers. In 2006, the EPA issued a second Section 114(a) request to Genco regarding projects at the Newton energy center. All of these facilities are coal-fired energy centers. In September 2008, the EPA issued a third Section 114(a) request regarding projects at all of Ameren's coal-fired energy centers in Illinois. We completed our response to the information requests, but we are unable to predict the outcome of this matter.

In January 2010, Ameren Missouri received a Notice of Violation from the EPA alleging violations of the Clean Air Act's NSR and Title V programs. In the Notice of Violation, the EPA contends that various projects at Ameren Missouri's Labadie, Meramec, Rush Island, and Sioux coal-fired energy centers, dating back to the mid-1990s, triggered NSR requirements. In October 2010, the EPA supplemented and amended the Notice of Violation to include additional projects at Ameren Missouri's coal-fired energy centers. In January 2011, the Department of Justice on behalf of the EPA filed a complaint against Ameren Missouri in the United States District Court for the Eastern District of Missouri. The EPA's complaint alleges that in performing projects at its Rush Island coal-fired energy center, Ameren Missouri violated provisions of the Clean Air Act and Missouri law. In June 2011, following the filing of motions to dismiss by Ameren Missouri, the Department of Justice amended its lawsuit to include additional Rush Island projects and to correct deficiencies in the initial complaint. At present, the complaint does not include Ameren Missouri's other coal-fired energy centers. Litigation of this matter could take many years to resolve. Ameren Missouri believes its defenses to the allegations described in the complaint as well as the original and amended Notice of Violation are meritorious. Ameren Missouri will defend itself vigorously. However, there can be no assurances that it will be successful in its efforts.

Ultimate resolution of these matters could have a material adverse impact on the future results of operations, financial position, and liquidity of Ameren, Ameren Missouri and Genco. A resolution could result in increased capital expenditures for the installation of pollution control equipment, increased operations and maintenance expenses, and fines or penalties. However, we are unable to predict the impact at this time.

Clean Water Act

In March 2011, the EPA announced a proposed rule applicable to cooling water intake structures at existing power plants that have the ability to withdraw greater than 2 million gallons of water per day from a water body and use at least 25 percent of that water exclusively for cooling. Under the proposed rule, affected facilities would need to meet mortality limits for aquatic life impinged on the plant's intake screens or reduce intake velocity to 0.5 feet per second. The proposed rule also requires plants to meet site-specific entrainment standards or reduce its cooling water intake flow commensurate with the intake flow of a closed-cycle cooling system. The final rule is scheduled to be issued in July 2012, with compliance expected within eight years thereafter. All coal-fired and nuclear energy centers at Ameren, Ameren Missouri and Genco with cooling water systems are subject to this proposed rule. The proposed rule did not mandate cooling towers at existing facilities as other technology options potentially could meet the site-specific standards. Ameren, Ameren Missouri and Genco are currently evaluating the proposed rule and their assessment of the proposed rule's impacts is ongoing. Therefore, we cannot predict at this time the capital or operating costs associated with compliance. The proposed rule could have an adverse effect on our results of operations, financial position, and liquidity if its implementation requires the installation of cooling towers at our electric generating stations.

In September 2009, the EPA announced its plan to revise the effluent guidelines applicable to steam electric generating units under the Clean Water Act. Effluent guidelines are national standards for wastewater discharges to surface water that are developed based on the effectiveness of available control technology. The EPA is engaged in information collection and analysis activities in support of this rulemaking and has indicated that it expects to issue a proposed rule in July 2012 and finalize the rule in 2014. We are unable at this time to predict the impact of this development.

Remediation

We are involved in a number of remediation actions to clean up hazardous waste sites as required by federal and state law. Such statutes require that responsible parties fund remediation actions regardless of their degree of fault, the legality of original disposal, or the ownership of a disposal site. Ameren Missouri and Ameren Illinois have each been identified by the federal or state governments as a potentially responsible party (PRP) at several contaminated sites. Several of these sites involve facilities that were transferred by our regulated utility operations in Illinois to Genco in May 2000 and to AERG in October 2003. As part of each transfer, Ameren Illinois has contractually agreed to indemnify Genco and AERG for remediation costs associated with preexisting environmental contamination at the transferred sites.

As of June 30, 2011, Ameren and Ameren Illinois owned or were otherwise responsible for 44 former MGP sites in Illinois. All of these sites are in various stages of investigation, evaluation, and remediation. Based on current estimated plans, Ameren and Ameren Illinois could substantially conclude remediation efforts at most of these sites by 2015. The ICC permits Ameren Illinois to recover remediation and litigation costs associated with its former MGP sites from its electric and natural gas utility customers through environmental adjustment rate riders. To be recoverable, such costs must be prudently and properly incurred. Costs are subject to annual review by the ICC.

As of June 30, 2011, Ameren and Ameren Missouri own or are otherwise responsible for 10 MGP sites in Missouri and one site in Iowa. Ameren Missouri does not currently have a rate rider mechanism that permits recovery of remediation costs associated with MGP sites from utility customers. Ameren Missouri does not have any retail utility operations in Iowa that would provide a source of recovery of these remediation costs.

The following table presents, as of June 30, 2011, the estimated probable obligation to remediate these MGP sites.


	Estimate
	Low		High		Recorded Liability^(a)
Ameren	$	121	$	199	$	121
Ameren Missouri		3		4		3
Ameren Illinois		118		195		118

(a)	Recorded liability represents the estimated minimum probable obligations, as no other amount within the range provided a better estimate.

Ameren Illinois is responsible for the cleanup of a former coal ash landfill in Coffeen, Illinois. As of June 30, 2011, Ameren Illinois estimated that obligation at $0.5 million to $6 million. Ameren Illinois recorded a liability of $0.5 million to represent its estimated minimum obligation for this site, as no other amount within the range was a better estimate. Ameren Illinois is also responsible for the cleanup of a landfill, underground storage tanks, and a water treatment plant in Illinois. As of June 30, 2011, Ameren Illinois recorded a liability of $0.8 million to represent its best estimate of the obligation for these sites.

Ameren Missouri has responsibility for the cleanup of two waste sites in Missouri as a result of federal agency mandates. One of the cleanup sites is a former coal tar distillery located in St. Louis, Missouri. In 2008, the EPA issued an administrative order to Ameren Missouri pertaining to this distillery operated by Koppers Company or its predecessor and successor companies. Ameren Missouri is the current owner of the site, but Ameren Missouri did not conduct any of the manufacturing operations involving coal tar or its byproducts. Ameren Missouri along with two other PRPs are currently performing a site investigation. As of June 30, 2011, Ameren Missouri estimated its obligation at $2 million to $5 million. Ameren Missouri has a liability of $2 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate. Ameren Missouri's other active federal agency-mandated cleanup site in Missouri is a site in Cape Girardeau. Ameren Missouri was a customer of an electrical equipment repair and disposal company that previously operated a facility at this site. A trust was established in the early 1990s by several businesses and governmental agencies to fund the cleanup of this site, which was completed in 2005. Ameren Missouri anticipates this trust fund will be sufficient to complete the remaining adjacent off-site clean-up and, therefore, has no recorded liability at June 30, 2011, related to this site.

Ameren Missouri also has a federal agency mandate to complete a site investigation for a site in Illinois. In 2000, the EPA notified Ameren Missouri and numerous other companies, including Solutia, that former landfills and lagoons in Sauget, Illinois, may contain soil and groundwater contamination. These sites are known as Sauget Area 2. From about 1926 until 1976, Ameren Missouri operated an energy center adjacent to Sauget Area 2. Ameren Missouri currently owns a parcel of property that was once used as a landfill. Under the terms of an Administrative Order on Consent, Ameren Missouri has joined with other PRPs to evaluate the extent of potential contamination with respect to Sauget Area 2.

The Sauget Area 2 investigations overseen by the EPA have been completed. The results have been submitted to the EPA, and a record of decision is expected in 2011. Once the EPA has selected a remedy, if any, it would begin negotiations with various PRPs regarding implementation. Over the last several years, numerous other parties have joined the PRP group. In addition, Pharmacia Corporation and Monsanto Company have agreed to assume the liabilities related to Solutia's former chemical waste landfill in the Sauget Area 2, notwithstanding Solutia's filing for bankruptcy protection. As of June 30, 2011, Ameren Missouri estimated its obligation at $0.4 million to $10 million. Ameren Missouri has a liability of $0.4 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate.

In December 2004, AERG submitted a plan to the Illinois EPA to address groundwater and surface water issues associated with the recycle pond, ash ponds, and reservoir at the Duck Creek energy center. In 2010, AERG closed the recycle pond system. Remediation work on the recycle pond was completed in the first quarter of 2011, and therefore no liability exists as of June 30, 2011.

Our operations or those of our predecessor companies involve the use of, disposal of, and in appropriate circumstances, the cleanup of substances regulated under environmental protection laws. We are unable to determine whether such practices will result in future environmental commitments or affect our results of operations, financial position, or liquidity.

Ash Management

There has been increased activity at both state and federal levels regarding additional regulation of ash pond facilities and CCR. In May 2010, the EPA announced proposed new regulations regarding the regulatory framework for the management and disposal of CCR, which could impact future disposal and handling costs at our energy centers. Those proposed regulations include two options for managing CCRs under either solid or hazardous waste regulations, but either alternative would allow for some continued beneficial uses, such as recycling, of CCR without classifying it as waste. As part of its proposal, the EPA is considering alternative regulatory approaches that require coal-fired power plants to either close surface impoundments, such as ash ponds, or retrofit such facilities with liners. Existing impoundments and landfills used for the disposal of CCR would be subject to groundwater monitoring requirements and requirements related to closure and postclosure care under the proposed regulations. Additionally, in January 2010, EPA announced its intent to develop regulations establishing financial responsibility requirements for the electric generation industry, among other industries, and specifically discussed CCR as a reason for developing the new requirements. Ameren, Ameren Missouri and Genco are currently evaluating all of the proposed regulations to determine whether current management of CCR, including beneficial reuse, and the use of the ash ponds should be altered. Ameren, Ameren Missouri and Genco also are evaluating the potential costs associated with compliance with the proposed regulation of CCR impoundments and landfills, which could be material, if such regulations are adopted.

In addition, the Illinois EPA requested that Ameren, Ameren Missouri and Genco establish groundwater monitoring plans for their ash impoundments in Illinois. Ameren and the Illinois EPA have established a framework for closure of ash ponds in Illinois, including the ash ponds at Venice, Hutsonville, and Duck Creek, when such facilities are ultimately taken out of service. In October 2010, the Illinois Pollution Control Board approved a site-specific plan for the closure of an ash pond at Genco's Hutsonville energy center. Those closure requirements include capping and covering the pond, groundwater monitoring, and the establishment of alternative groundwater standards. In May 2011, the Illinois EPA approved a site-specific closure and groundwater management plan for the ash ponds at Ameren Missouri's Venice energy center, similar to the approved plan for Hutsonville. Similar closure requirements and groundwater management plans for ash ponds at the Duck Creek energy center are being developed. Ameren, Ameren Missouri and Genco have recorded AROs, based on current laws, for the estimated costs of the retirement of their ash ponds.

Pumped-storage Hydroelectric Energy Center Breach

In December 2005, there was a breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center. This resulted in significant flooding in the local area, which damaged a state park. Ameren Missouri settled with FERC and the state of Missouri all issues associated with the December 2005 Taum Sauk incident. The rebuilt Taum Sauk energy center became fully operational in April 2010.

Ameren Missouri had property and liability insurance coverage for the Taum Sauk incident, subject to certain limits and deductibles. Insurance did not cover some lost electric margins or penalties paid to FERC. Ameren Missouri believes that the total cost for cleanup, damage and liabilities, excluding costs to rebuild the upper reservoir, is approximately $208 million, which is the amount Ameren Missouri had paid as of June 30, 2011. As of June 30, 2011, Ameren Missouri had recorded expenses of $36 million, primarily in prior years, for items not covered by insurance. Ameren Missouri recorded a $172 million receivable for amounts recoverable from insurance companies under liability coverage. As of June 30, 2011, Ameren Missouri had received $104 million from insurance companies for liability claims, which reduced the insurance receivable balance subject to liability coverage to $68 million.

In June 2010, Ameren Missouri sued an insurance company that was providing Ameren Missouri with liability coverage on the date of the Taum Sauk incident. In the litigation, filed in the United States District Court for the Eastern District of Missouri, Ameren Missouri claimed the insurance company breached its duty to indemnify Ameren Missouri for the losses experienced from the incident. In January 2011, the court ruled that the parties must first pursue alternative dispute resolution under the terms of their coverage agreement. In February 2011, Ameren Missouri filed an appeal of the January ruling with the United States Court of Appeals for the Eighth Circuit, seeking the ability to pursue resolution of this dispute outside of a dispute resolution process under the terms of its coverage agreement.

Until Ameren's remaining liability insurance claims and the related litigation are resolved, we are unable to determine the total impact the breach could have on Ameren's and Ameren Missouri's results of operations, financial position, and liquidity beyond those amounts already recognized. Ameren Missouri included certain capitalized costs associated with enhancements, or costs that could have been incurred absent the breach, at the rebuilt Taum Sauk energy center not recovered from property insurers in its recently completed electric rate case. However, in the July 2011 rate order, the MoPSC disallowed all of the capitalized costs associated with the rebuilding of the Taum Sauk energy center. As a result of the order, Ameren and Ameren Missouri will each record, in the third quarter ending September 30, 2011, a pretax charge to earnings of $89 million to reflect this disallowance. See Note 2 - Rate and Regulatory Matters for additional information about the MoPSC's July 2011 electric rate order.

Asbestos-related Litigation

Ameren, Ameren Missouri, Ameren Illinois and EEI have been named, along with numerous other parties, in a number of lawsuits filed by plaintiffs claiming varying degrees of injury from asbestos exposure. Most have been filed in the Circuit Court of Madison County, Illinois. The total number of defendants named in each case varies, with as many as 212 parties named in some pending cases and as few as two in others. However, in the cases that were pending as of June 30, 2011, the average number of parties was 78.

The claims filed against Ameren, Ameren Missouri, Ameren Illinois and Genco allege injury from asbestos exposure during the plaintiffs' activities at our present or former energy centers. Former CIPS energy centers are now owned by Genco, and former CILCO energy centers are now owned by AERG. As a part of the transfer of ownership of the CIPS and CILCO energy centers, CIPS and CILCO, now Ameren Illinois, contractually agreed to indemnify Genco and AERG, for liabilities associated with asbestos-related claims arising from activities prior to the transfer. Each lawsuit seeks unspecified damages that, if awarded at trial, typically would be shared among the various defendants.

The following table presents the pending asbestos-related lawsuits filed against the Ameren Companies as of June 30, 2011:


Ameren	AMO	AIC	Genco	Total^(a)
5	54	74	(b)	95

(a)	Total does not equal the sum of the subsidiary unit lawsuits because some of the lawsuits name multiple Ameren entities as defendants.

(b)	As of June 30, 2011, eight asbestos-related lawsuits were pending against EEI. The general liability insurance maintained by EEI provides coverage with respect to liabilities arising from asbestos-related claims.

At June 30, 2011, Ameren, Ameren Missouri, Ameren Illinois and Genco had liabilities of $19 million, $7 million, $12 million, and $- million, respectively, recorded to represent their best estimate of their obligations related to asbestos claims.

Ameren Illinois has a tariff rider to recover the costs of asbestos-related litigation claims, subject to the following terms: 90% of cash expenditures in excess of the amount included in base electric rates are recovered from a trust fund established when Ameren acquired IP. At June 30, 2011, the trust fund balance was approximately $23 million, including accumulated interest. If cash expenditures are less than the amount in base rates, Ameren Illinois will contribute 90% of the difference to the fund. Once the trust fund is depleted, 90% of allowed cash expenditures in excess of base rates will be recovered through charges assessed to customers under the tariff rider. Following the Ameren Illinois Merger, this rider is only applicable for claims that occurred within IP's historical service territory. Similarly, the rider will seek recovery only from customers within IP's historical service territory.

Illinois Sales and Use Tax Exemptions and Credits

In Exelon Corporation v. Department of Revenue, the Illinois Supreme Court decided in 2009 that electricity is tangible personal property for purposes of the Illinois income tax investment credit. In March 2010, the United States Supreme Court refused to hear the case, and the case became final. During the second quarter of 2010, Genco and AERG began claiming Illinois sales and use tax exemptions and credits for purchase transactions related to their generation operations. The basis for those claims is that the determination in the Exelon case that electricity is tangible personal property applies to sales and use tax manufacturing exemptions and credits. While it is possible that Illinois will take the position that Genco and AERG do not qualify for the manufacturing exemptions and credits, we do not believe that it is probable that Illinois will prevail and therefore have not recorded a charge to earnings for the loss contingency. Since the second quarter of 2010 through June 30, 2011, Ameren and Genco claimed manufacturing exemptions and credits of $19 million and $13 million, respectively.

The Ameren Companies believe that the final disposition of these proceedings will not have a material adverse effect on their results of operations, financial position, or liquidity.

Commitments and Contingencies

NOTE 9 - COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax and regulatory proceedings before various courts, regulatory commissions, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in the notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.

Reference is made to Note 1 - Summary of Significant Accounting Policies, Note 2 - Rate and Regulatory Matters, Note 14 - Related Party Transactions, and Note 15 - Commitments and Contingencies under Part II, Item 8 of the Form 10-K. See also Note 1 - Summary of Significant Accounting Policies, Note 2 - Rate and Regulatory Matters, Note 8 - Related Party Transactions and Note 10 - Callaway Energy Center in this report.

Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri's Callaway energy center at June 30, 2011. The property coverage and the nuclear liability coverage must be renewed on April 1 and January 1, respectively, of each year.


Type and Source of Coverage	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	$	375		$	-
Pool participation		12,219	^(a)		118	^(b)
	$	12,594	^(c)	$	118
Property damage:
Nuclear Electric Insurance Ltd.	$	2,750	^(d)	$	23
Replacement power:
Nuclear Electric Insurance Ltd.	$	490	^(e)	$	9
Energy Risk Assurance Company	$	64	^(f)	$	-

(a)	Provided through mandatory participation in an industry-wide retrospective premium assessment program.

(b)	Retrospective premium under Price-Anderson. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed U.S. commercial reactor, payable at $17.5 million per year.

(c)

Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $118 million per incident for each licensed reactor it operates with a maximum of $17.5 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

(d)	Provides for $500 million in property damage and decontamination, excess property insurance, and premature decommissioning coverage up to $2.25 billion for losses in excess of the $500 million primary coverage.

(e)

Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first eight weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million.

(f)

Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. The coverage commences after the first 52 weeks of insurance coverage from Nuclear Electric Insurance Ltd. and is for a weekly indemnity of $900,000 for 71 weeks in excess of the $3.6 million per week set forth above. Energy Risk Assurance Company is an affiliate and has reinsured this coverage with third-party insurance companies. See Note 8 - Related Party Transactions for more information on this affiliate transaction.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear power facility. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The five-year inflationary adjustment as prescribed by the most recent Price-Anderson Act renewal was effective October 29, 2008. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by Price-Anderson.

Losses resulting from terrorist attacks are covered under Nuclear Electric Insurance Ltd.'s policies, subject to an industry-wide aggregate policy limit of $3.24 billion within a 12-month period for coverage for such terrorist acts.

If losses from a nuclear incident at the Callaway energy center exceed the limits of, or are not covered by, insurance, or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren's and Ameren Missouri's results of operations, financial position, or liquidity.

Other Obligations

To supply a portion of the fuel requirements of our energy centers, we have entered into various long-term commitments for the procurement of coal, natural gas and nuclear fuel. We have also entered into various long-term commitments for the purchase of electric capacity and natural gas for distribution. For a complete listing of our obligations and commitments, see Note 15 - Commitments and Contingencies under Part II, Item 8, of the Form 10-K.

Our commitments for the procurement of coal have materially increased from the amounts previously disclosed in the Form 10-K. In July 2011, Ameren Missouri entered into multi-year agreements to procure ultra low-sulfur coal and the related transportation, from the Powder River Basin in Wyoming. The following table presents our total estimated coal procurement and related transportation commitments at July 19, 2011, including the July 2011 ultra low-sulfur coal and the related transportation agreements:


	2011		2012		2013		2014		2015		Thereafter
Ameren	$	669	$	1,153	$	801	$	643	$	634	$	1,651
Ameren Missouri		244		618		609		630		620		1,589

Ameren's and Ameren Illinois' commitments for the procurement of purchased power have materially changed due to the 2011 RFP process administered by the IPA in the second quarter from amounts previously disclosed in Form 10-K as of December 31, 2010. See also Note 8 - Related Party Transactions in this report. The following table presents our total estimated purchased power commitments at June 30, 2011:


	2011		2012		2013		2014		2015		Thereafter
Ameren	$	178	$	200	$	314	$	129	$	55	$	826
Ameren Illinois		165		177		290		106		32		624

Environmental Matters

We are subject to various environmental laws and regulations enforced by federal, state and local authorities. From the beginning phases of siting and development to the ongoing operation of existing or new electric generating, transmission and distribution facilities, natural gas storage facilities, and natural gas transmission and distribution facilities, our activities involve compliance with diverse environmental laws and regulations. These laws and regulations address emissions, impacts to air, land and water, noise, protected natural and cultural resources (such as wetlands, endangered species and other protected wildlife, and archeological and historical resources), and chemical and waste handling. Complex and lengthy processes are required to obtain approvals, permits, or licenses for new, existing or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials (including wastes) requires release prevention plans and emergency response procedures.

In addition to existing laws and regulations governing our facilities, the EPA is developing numerous new environmental regulations that will have a significant impact on the electric utility industry. These regulations could be particularly burdensome for certain companies, including Ameren, Ameren Missouri and Genco, that operate coal-fired energy centers. Significant new rules already proposed or promulgated since the beginning of 2010 include the regulation of greenhouse gas emissions; revised ambient air quality standards for SO₂ and NO₂ emissions increasing the stringency of the existing ozone national ambient air quality standard; the CSAPR, which will require further reduction of SO₂ and NO_x emissions from power plants; a regulation governing management of CCR and coal ash impoundments; MACT standards for the control of hazardous air pollutants, such as mercury, metals, and acid gases from power plants; revised NSPS for particulate matter, SO₂ and NO_x emissions from new sources; and new regulations under the Clean Water Act, that could require significant capital expenditures such as new water intake structures or cooling towers at our energy centers. Within the next year, the EPA is also expected to propose NSPS and emission guidelines for greenhouse gas emissions applicable to new and existing electric generating units as well as further reductions in the annual national ambient air quality standards for ozone and fine particulates. The EPA also plans to propose an additional rule governing air pollutant transport, but has not specified when it will issue that proposal. These new regulations may be challenged with lawsuits, so the timing of their ultimate implementation is uncertain. Although many details of these future regulations are unknown, the combined effects of the new and proposed environmental regulations may result in significant capital expenditures and/or increased operating costs over the next five to ten years for Ameren, Ameren Missouri and Genco. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. As a result, these regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of plant assets. Failure to comply with environmental laws and regulations may also result in the imposition of fines, penalties, and injunctive measures.

The estimates in the table below contain all of the known capital costs to comply with existing environmental regulations and our preliminary assessment of the potential impacts of the EPA's proposed regulation for CCR, the proposed MACT standard for the control of mercury and other hazardous air pollutants, the finalized CSAPR, and the revised national ambient air quality standards for SO₂ and NO₂ emissions as of June 30, 2011. The estimates in the table below assume that CCR will continue to be regarded as nonhazardous. The estimates in the table below do not include the impacts of new regulations proposed by the EPA under the Clean Water Act in March 2011 regarding cooling water intake structures as our evaluation of those impacts is ongoing. The estimates shown in the table below could change significantly depending upon additional federal or state requirements, regulation of greenhouse gas emissions, new hourly national ambient air quality standards or changes to existing standards for SO₂ and NO₂ emissions, the final requirements under a MACT standard for the control of hazardous air pollutants such as mercury, metals, and acid gases, additional rules governing air pollutant transport, finalized regulations under the Clean Water Act, CCR being classified as hazardous, our finalized CSAPR compliance plans, new technology, variations in costs of material or labor, or alternative compliance strategies, among other factors. Ameren Missouri's estimate in the table below includes the impacts of its July 2011 multi-year agreement, to procure ultra low-sulfur coal. This change in fuel mix is estimated to eliminate or postpone past 2020, $1.1 billion of Ameren Missouri's capital expenditures for pollution control equipment compared with the estimated capital expenditures included in the Form 10-K. In addition, the estimates for Genco and AERG in the table below have been updated from the estimates provided in the Form 10-K, based on the Merchant Generation segment's continued optimization of environmental compliance plans.


	2011		2012 - 2015					2016 - 2020					Total
AMO^(a)	$	40	$	315	-	$	390	$	905	-	$	1,105	$	1,260	-	$	1,535
Genco		125		355	-		435		60	-		75		540	-		635
AERG		10		170	-		210		10	-		15		190	-		235
Ameren	$	175	$	840	-	$	1,035	$	975	-	$	1,195	$	1,990	-	$	2,405

(a)	Ameren Missouri's expenditures are expected to be recoverable from ratepayers.