COMMITMENTS AND CONTINGENCIES

Commitments - Operating leases represent future minimum lease payments under noncancelable leases, which primarily includes office space, pipeline equipment, rail cars and information technology equipment. Rental expense in 2018, 2017 and 2016 was not material. We have no material operating leases. We lease certain compression facilities under a capital lease that has a fixed-price purchase option in 2028. Firm transportation and storage contracts are fixed-price contracts that provide us with firm transportation and storage capacity. The following table sets forth our capital lease future minimum payments and our firm transportation and storage contract payments for the periods indicated:



	Capital Lease (a)		Firm Transportation and Storage Contracts
	(Millions of dollars)
2019	$	4.5	$	63.7
2020	4.5		51.6
2021	4.5		35.7
2022	4.5		22.4
2023	4.5		17.3
Thereafter	21.6		11.7
Total	$	44.1	$	202.4
(a) - At December 31, 2018, $28 million in principal represents noncash financing activities.

Environmental Matters and Pipeline Safety - The operation of pipelines, plants and other facilities for the gathering, processing, transportation and storage of natural gas, NGLs, condensate and other products is subject to numerous and complex laws and regulations pertaining to health, safety and the environment. As an owner and/or operator of these facilities, we must comply with laws and regulations that relate to air and water quality, hazardous and solid waste management and disposal, cultural resource protection and other environmental matters. The cost of planning, designing, constructing and operating pipelines, plants and other facilities must incorporate compliance with these laws and regulations and safety standards. Failure to comply with these laws and regulations may trigger a variety of administrative, civil and potentially criminal enforcement measures, including citizen suits, which can include the assessment of monetary penalties, the imposition of remedial requirements and the issuance of injunctions or restrictions on operation or construction. Management believes that, based on currently known information, compliance with these laws and regulations will not have a material adverse effect on our results of operations, financial condition or cash flows.

Legal Proceedings - Gas Index Pricing Litigation - As previously reported, we and our affiliate, ONEOK Energy Services Company, L.P. (OESC), along with several other energy companies, were named as defendants in multiple lawsuits arising from alleged market manipulation or false reporting of natural gas prices to natural gas-index publications alleged to have occurred prior to 2003.

In March 2017, the United States District Court for the District of Nevada (the Nevada District Court) granted summary judgment to OESC in Sinclair Oil Corporation v. ONEOK Energy Services Company, L.P. (filed in the United States District Court for the District of Wyoming (the Wyoming District Court) in September 2005, transferred to MDL-1566 in the Nevada District Court). In September 2017, the Nevada District Court entered a final judgment in favor of OESC in Sinclair, which was appealed by Sinclair Oil Corporation to the Ninth Circuit Court of Appeals. On August 1, 2018, the Ninth Circuit Court of Appeals reversed the Nevada District Court’s granting of summary judgment and remanded the case back to the Nevada District Court. On February 11, 2019, Sinclair was further remanded back to the Wyoming District Court. We expect that future charges, if any, from the ultimate resolution of the Sinclair case will not be material to our results of operations, financial position or cash flows.

Other Legal Proceedings - We are a party to various other litigation matters and claims that have arisen in the normal course of our operations. While the results of these litigation matters and claims cannot be predicted with certainty, we believe the reasonably possible losses from such matters, individually and in the aggregate, are not material. Additionally, we believe the probable final outcome of such matters will not have a material adverse effect on our consolidated results of operations, financial position or cash flows.