Exhibit 99.1

Investor Contact: Larry P. Kromidas

 lpkromidas@olin.com

(618) 258-3206

 News

Olin Corporation, 190 Carondelet Plaza, Suite 1530, Clayton, MO 63105-3443

FOR IMMEDIATE RELEASE

OLIN ANNOUNCES FIRST QUARTER EARNINGS

WINCHESTER POSTS RECORD FIRST QUARTER

Clayton, Mo., April 26, 2010- Olin Corporation (NYSE: OLN) announced today that its first quarter 2010 net income was $14.1 million, or $0.18 per diluted share, which compares to $46.7 million, or $0.60 per diluted share in the first quarter of 2009.  Sales in the first quarter of 2010 were $362.0 million, compared to $400.6 million in the first quarter of 2009.

Joseph D. Rupp, Chairman, President, and Chief Executive Officer said, “Winchester achieved the highest level of first quarter earnings in its history, and the second best quarterly results ever, reflecting the continuation of the stronger than normal demand that began in the fourth quarter of 2008.  In the first quarter of 2010, Winchester benefited from lower commodity costs and reduced bad debt related expenses compared to the first quarter of 2009, which more than offset lower sales volumes.  First quarter 2010 Winchester volumes remained well above 2008 levels.  Winchester’s first quarter 2010 segment earnings were $19.5 million compared to $17.0 million in the first quarter of 2009.

“Chlor Alkali first quarter 2010 segment earnings of $10.6 million reflected a sequential improvement from the fourth quarter of 2009 earnings of $5.2 million. Both ECU netbacks and product volumes improved from the fourth quarter of 2009.  First quarter 2010 Chlor Alkali segment earnings include approximately $1.4 million of costs directly associated with the first quarter force majeure event at the McIntosh, Alabama facility.  The first quarter 2010 Chlor Alkali operating rate was 75%, which was higher than the fourth quarter 2009 level of 70%.

“First quarter 2010 earnings include $2.6 million of pretax recoveries from third parties of environmental costs incurred and expensed in prior periods, a $1.3 million pretax charge associated with an agreement to withdraw from a multi-employer defined benefit pension plan, and $3.8 million of favorable adjustments to income tax expense.

“Second quarter 2010 net income is forecast to be in the $0.15 to $0.20 per diluted share range.  Second quarter 2010 Chlor Alkali segment earnings are expected to more than double compared to the first quarter of 2010 reflecting both improved pricing and improved demand.  Segment earnings for Winchester are projected to decline from first quarter levels primarily due to higher commodity costs.  Charges to income for environmental and remedial activities are forecast to increase to the $6 million to $8 million range in the second quarter of 2010.  This second quarter 2010 forecast for environmental and remedial costs does not include any recovery of costs incurred and expensed in prior periods.  The second quarter 2010 forecast includes approximately $2 million of favorable adjustments to income tax expense.”

SEGMENT REPORTING

We define segment earnings as income (loss) before interest expense, interest income, other operating income, other income, and income taxes and include the results of non-consolidated affiliates in segment results consistent with management’s monitoring of the operating segments.

CHLOR ALKALI PRODUCTS

Chlor Alkali product sales for the first quarter of 2010 were $230.6 million compared to $267.7 million in the first quarter of 2009.  First quarter 2010 chlorine and caustic soda volumes increased 20% compared to the first quarter 2009 levels.  Volumes for potassium hydroxide more than tripled in the first quarter of 2010 primarily reflecting a raw material supply disruption that impacted first quarter 2009 volumes.  Bleach volumes increased 12% during the first quarter of 2010 compared to the first quarter of 2009, while volumes for hydrochloric acid declined 23% compared to first quarter 2009 levels.  ECU netbacks in the first quarter of 2010 decreased by 42% compared to the first quarter of 2009.  Freight costs included in the ECU netbacks decreased 6% in the first quarter of 2010 compared to the first quarter of 2009, which reflects the benefits of increased pipeline shipments associated with the restart of the St. Gabriel, Louisiana facility.  First quarter 2010 Chlor Alkali segment earnings were $10.6 million compared to $68.7 million in the first quarter of 2009, due to lower prices, which more than offset higher volumes and lower bad debt expenses.

WINCHESTER

Winchester first quarter 2010 sales were $131.4 million compared to $132.9 million in the first quarter of 2009.  This decrease primarily reflects lower sales volumes.  Commercial sales decreased during the quarter which more than offset increases in military, law enforcement and industrial sales.  Winchester’s first quarter 2010 segment earnings were $19.5 million compared to $17.0 million in the first quarter of 2009.  The increase in segment earnings reflects the lower material and bad debt costs, which more than offset lower commercial volumes.

CORPORATE AND OTHER COSTS

Pension income included in the first quarter 2010 Corporate and Other segment was $4.7 million, compared to income of $4.8 million in the first quarter of 2009.  First quarter 2010 pension income included a $1.3 million charge associated with an agreement to withdraw the Henderson, Nevada chlor alkali hourly workforce from a multi-employer defined benefit pension plan.

First quarter credits to income for environmental investigatory and remedial activities were $2.0 million in 2010, which includes the $2.6 million of pretax recoveries for costs incurred and expensed in prior periods.  Without these recoveries, charges to income for environmental investigatory and remedial activities would have been $0.6 million in the first quarter of 2010 compared to $4.8 million in the first quarter of 2009.  These charges relate primarily to remedial and investigatory activities associated with former waste sites and past operations.

Other corporate and unallocated costs in the first quarter of 2010 increased $1.5 million compared to the first quarter of 2009.  Stock based compensation costs increased in the first quarter of 2010 compared to the first quarter of 2009 due to higher mark-to-market adjustments.

INCOME TAX EXPENSE

First quarter 2010 income tax expense includes $3.8 million of adjustments from prior periods reflecting a $1.8 million reduction in expense related to the expiration of the statute of limitations in domestic jurisdictions, a $1.6 million reduction in expense related to the release of a valuation allowance associated with foreign tax credits generated by our Canadian operations, and a $0.4 million benefit related to prior years’ tax returns.

DIVIDEND

On April 22, 2010, Olin’s Board of Directors declared a dividend of $0.20 on each share of Olin common stock.  The dividend is payable on June 10, 2010 to shareholders of record at the close of business on May 10, 2010.  This is the 334th consecutive dividend to be paid by the Company.

CONFERENCE CALL INFORMATION

The Company’s first quarter earnings conference call with securities analysts is scheduled for 11:00 A.M. Eastern Time, Tuesday, April 27.  The call will feature remarks by Joseph D. Rupp, Olin’s Chairman, President and Chief Executive Officer; John E. Fischer, Olin’s Vice President and Chief Financial Officer; John L. McIntosh, Vice President and President Chlor Alkali Products Division; and Larry P. Kromidas, Olin’s Assistant Treasurer and Director, Investor Relations.  Anyone wishing to listen to the call may do so via the Internet by following the instructions posted under the Conference Call icon on Olin’s website, www.olin.com.  Listeners should log on to the website at least 5 minutes before the call.  The call will also be audio archived on the Olin website for future replay.  A transcript of the conference call will be available on the website in the Investor section later in the day.

COMPANY DESCRIPTION

Olin Corporation is a manufacturer concentrated in two business segments:  Chlor Alkali Products and Winchester.  Chlor Alkali Products manufactures chlorine and caustic soda, sodium hydrosulfite, hydrochloric acid, hydrogen, potassium hydroxide and bleach products.  Winchester products include sporting ammunition, reloading components, small caliber military ammunition and components, and industrial cartridges.

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FORWARD-LOOKING STATEMENTS

This communication includes forward-looking statements. These statements relate to analyses and other information that are based on management's beliefs, certain assumptions made by management, forecasts of future results, and current expectations, estimates and projections about the markets and economy in which we and our various segments operate. The statements contained in this communication that are not statements of historical fact may include forward-looking statements that involve a number of risks and uncertainties.

We have used the words "anticipate," "intend," "may," "expect," "believe," "should," "plan," "project," "estimate," “forecast,” and variations of such words and similar expressions in this communication to identify such forward-looking statements. These statements are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict and many of which are beyond our control. Therefore, actual outcomes and results may differ materially from those matters expressed or implied in such forward-looking statements. We undertake no obligation to update publicly any forward-looking statements, whether as a result of future events, new information or otherwise. Relative to the dividend, the payment of cash dividends is subject to the discretion of our board of directors and will be determined in light of then-current conditions, including our earnings, our operations, our financial conditions, our capital requirements and other factors deemed relevant by our board of directors. In the future, our board of directors may change our dividend policy, including the frequency or amount of any dividend, in light of then-existing conditions.

The risks, uncertainties and assumptions involved in our forward-looking statements, many of which are discussed in more detail in our filings with the SEC, including without limitation the “Risk Factors” section of our Annual Report on Form 10-K for the year ended December 31, 2009, include, but are not limited to, the following:

·   sensitivity to economic, business and market conditions in the United States and overseas, including economic instability or a downturn in the sectors served by us, such as ammunition, housing, vinyls, and pulp and paper, and the migration by United States customers to low-cost foreign locations;

·   the cyclical nature of our operating results, particularly declines in average selling prices in the chlor alkali industry and the supply/demand balance for our products, including the impact of excess industry capacity or an imbalance in demand for our chlor alkali products;

·   economic and industry downturns that result in diminished product demand and excess manufacturing capacity in any of our segments and that, in many cases, result in lower selling prices and profits;

·   costs and other expenditures in excess of those projected for environmental investigation and remediation or other legal proceedings;

·   changes in legislation or government regulations or policies, including proposed legislation that would phase out the use of mercury in the manufacture of chlorine, caustic soda, and related products;

·   unexpected litigation outcomes;

·   new regulations or public policy changes regarding the transportation of hazardous chemicals and the security of chemical manufacturing facilities;

·   the occurrence of unexpected manufacturing interruptions and outages, including those occurring as a result of labor disruptions and production hazards;

·   higher-than-expected raw material and energy, transportation, and/or logistics costs;

·   continuing weak industry conditions could affect our ability to comply with the financial maintenance covenants in our senior revolving credit facility and our accounts receivable facility;

·   the effects of any declines in global equity markets on asset values and any declines in interest rates used to value the liabilities in our pension plan;

·   an increase in our indebtedness or higher-than-expected interest rates, affecting our ability to generate sufficient cash flow for debt service; and

·   adverse conditions in the credit and capital markets, limiting or preventing our ability to borrow or raise capital.

All of our forward-looking statements should be considered in light of these factors. In addition, other risks and uncertainties not presently known to us or that we consider immaterial could affect the accuracy of our forward-looking statements.

2010 - 09

Olin Corporation

Consolidated Statements of Income(a)

	Three Months
	Ended March 31,
(In millions, except per share amounts)	2010		2009
Sales	$	362.0	$	400.6
Operating Expenses:
Cost of Goods Sold		312.5		306.2
Selling and Administration		32.1		39.2
Other Operating Income(b)		2.3		5.5
Operating Income		19.7		60.7
Earnings of Non-consolidated Affiliates		2.2		14.8
Interest Expense(c)		6.9		1.6
Interest Income		0.2		0.5
Income before Taxes		15.2		74.4
Income Tax Provision		1.1		27.7
Net Income	$	14.1	$	46.7
Net Income Per Common Share:
Basic	$	0.18	$	0.60
Diluted	$	0.18	$	0.60
Dividends Per Common Share	$	0.20	$	0.20
Average Common Shares Outstanding - Basic		78.8		77.5
Average Common Shares Outstanding - Diluted		79.4		77.6

(a)	Unaudited.
(b)	Other operating income for the three months ended March 31, 2010 and 2009 included $2.0 million and $1.3 million, respectively, of gains on the disposal of assets primarily associated with the St. Gabriel, LA conversion and expansion project.  Other operating income for the three months ended March 31, 2009 also included a $3.7 million gain on the sale of land.
(c)	Interest expense was reduced by capitalized interest of $0.1 million and $2.5 million for the three months ended March 31, 2010 and 2009, respectively.

Olin Corporation

Segment Information(a)

	Three Months
	Ended March 31,
(In millions)	2010			2009
Sales:
Chlor Alkali Products	$	230.6		$	267.7
Winchester		131.4			132.9
Total Sales	$	362.0		$	400.6
Income before Taxes:
Chlor Alkali Products(b)	$	10.6		$	68.7
Winchester		19.5			17.0
Corporate/Other:
Pension Income(c)		4.7			4.8
Environmental Income (Expense)(d)		2.0			(4.8	)
Other Corporate and Unallocated Costs		(17.2	)		(15.7	)
Other Operating Income(e)		2.3			5.5
Interest Expense(f)		(6.9	)		(1.6	)
Interest Income		0.2			0.5
Income before Taxes	$	15.2		$	74.4

(a)	Unaudited.
(b)	Earnings of non-consolidated affiliates are included in the Chlor Alkali Products segment results consistent with management's monitoring of the operating segments. The earnings from non-consolidated affiliates were $2.2 million and $14.8 million for the three months ended March 31, 2010 and 2009, respectively.
(c)	The service cost and the amortization of prior service cost components of pension expense related to the employees of the operating segments are allocated to the operating segments based on their respective estimated census data.  All other components of pension costs are included in Corporate/Other and include items such as the expected return on plan assets, interest cost and recognized actuarial gains and losses.  Pension income for the three months ended March 31, 2010 included a charge of $1.3 million associated with an agreement to withdraw our Henderson, NV chlor alkali hourly workforce from a multi-employer defined benefit pension plan.
(d)	Environmental income (expense) for the three months ended March 31, 2010 included $2.6 million of recoveries from third parties for costs incurred and expensed in prior periods.
(e)	Other operating income for the three months ended March 31, 2010 and 2009 included $2.0 million and $1.3 million, respectively, of gains on the disposal of assets primarily associated with the St. Gabriel, LA conversion and expansion project.  Other operating income for the three months ended March 31, 2009 also included a $3.7 million gain on the sale of land.
(f)	Interest expense was reduced by capitalized interest of $0.1 million and $2.5 million for the three months ended March 31, 2010 and 2009, respectively.

Olin Corporation

Consolidated Balance Sheets(a)

	March 31,			December 31,			March 31,
(In millions, except per share data)	2010			2009			2009
Assets:
Cash & Cash Equivalents	$	411.0		$	458.5		$	168.6
Accounts Receivable, Net		197.1			183.3			216.4
Income Taxes Receivable		19.3			19.4			2.7
Inventories		156.4			123.8			166.5
Current Deferred Income Taxes		50.1			50.5			60.1
Other Current Assets		22.3			24.8			11.5
Total Current Assets		856.2			860.3			625.8
Property, Plant and Equipment
(Less Accumulated Depreciation of $1,017.5, $1,001.3 and $970.6)		688.5			695.4			659.4
Prepaid Pension Costs		14.5			5.0			—
Deferred Income Taxes		—			—			23.5
Other Assets		71.8			71.0			83.3
Goodwill		300.3			300.3			301.9
Total Assets	$	1,931.3		$	1,932.0		$	1,693.9
Liabilities and Shareholders' Equity:
Accounts Payable	$	121.1		$	117.8		$	124.2
Accrued Liabilities		192.4			193.1			202.6
Total Current Liabilities		313.5			310.9			326.8
Long-Term Debt		397.1			398.4			253.4
Accrued Pension Liability		55.7			56.6			43.3
Deferred Income Taxes		26.6			25.8			6.0
Other Liabilities		316.4			318.0			304.3
Total Liabilities		1,109.3			1,109.7			933.8
Commitments and Contingencies
Shareholders' Equity:
Common Stock, Par Value $1 Per Share, Authorized 120.0 Shares:
Issued and Outstanding 78.9 Shares (78.7 and 77.9 in 2009)		78.9			78.7			77.9
Additional Paid-In Capital		826.8			823.1			809.3
Accumulated Other Comprehensive Loss		(250.7	)		(248.2	)		(253.8	)
Retained Earnings		167.0			168.7			126.7
Total Shareholders' Equity		822.0			822.3			760.1
Total Liabilities and Shareholders' Equity	$	1,931.3		$	1,932.0		$	1,693.9

(a) Unaudited

Olin Corporation

Consolidated Statements of Cash Flows(a)

	Three Months Ended March 31,
(In millions)	2010			2009
Operating Activities:
Net Income	$	14.1		$	46.7
Earnings of Non-consolidated Affiliates		(2.2	)		(14.8	)
Gains on Disposition of Property, Plant and Equipment		(2.0	)		(5.0	)
Stock-Based Compensation		1.5			1.1
Depreciation and Amortization		21.6			16.6
Deferred Income Taxes		2.5			21.2
Qualified Pension Plan Contributions		(2.4	)		(1.0	)
Qualified Pension Plan Income		(6.0	)		(5.0	)
Common Stock Issued Under Employee Benefit Plans		0.3			0.6
Changes in:
Receivables		(13.8	)		(3.4	)
Income Taxes Receivable		0.1			(3.3	)
Inventories		(32.6	)		(35.1	)
Other Current Assets		(4.4	)		(0.6	)
Accounts Payable and Accrued Liabilities		8.8			(46.3	)
Other Assets		(0.1	)		—
Other Noncurrent Liabilities		0.4			0.8
Other Operating Activities		(0.2	)		0.2
Net Operating Activities		(14.4	)		(27.3	)
Investing Activities:
Capital Expenditures		(21.4	)		(49.8	)
Proceeds from Disposition of Property, Plant and Equipment		2.5			5.5
(Advances to) Distributions from Affiliated Companies, Net		(0.2	)		1.4
Other Investing Activities		(0.4	)		(0.3	)
Net Investing Activities		(19.5	)		(43.2	)
Financing Activities:
Long Term Debt Borrowings		—			1.5
Issuance of Common Stock		2.2			6.6
Dividends Paid		(15.8	)		(15.5	)
Net Financing Activities		(13.6	)		(7.4	)
Net Decrease in Cash and Cash Equivalents		(47.5	)		(77.9	)
Cash and Cash Equivalents, Beginning of Year		458.5			246.5
Cash and Cash Equivalents, End of Period	$	411.0		$	168.6

(a) Unaudited