Whistler Pipeline Placed in Service

The Whistler Pipeline began full commercial service on July 1st, 2021 providing approximately 2.0 billion cubic feet per day (Bcf/d) of incremental natural gas transport capacity to the Texas Gulf Coast markets from the Permian basin, which will help ensure sufficient reliable gas takeaway and reduce natural gas flaring in the Permian basin. The delivery points in the Agua Dulce provide shippers with access to Gulf Coast industrial and export markets including LNG.

The Whistler Pipeline is 100% owned by Whistler Pipeline LLC, which is a consortium made up of MPLX LP (NYSE: MPLX), WhiteWater and a joint venture between Stonepeak Infrastructure Partners (Stonepeak) and West Texas Gas, Inc. (WTG).

ABOUT THE WHISTLER PIPELINE

The Whistler Pipeline is an approximately 450-mile, 42-inch intrastate pipeline that transports natural gas from the Waha Header in the Permian Basin to Agua Dulce, Texas, providing direct access to South Texas and export markets. An approximately 50-mile 36-inch lateral provides connectivity to the Midland Basin.

About MPLX LP

MPLX is a diversified, large-cap master limited partnership that owns and operates midstream energy infrastructure and logistics assets, and provides fuels distribution services. MPLX's assets include a network of crude oil and refined product pipelines; an inland marine business; light-product terminals; storage caverns; refinery tanks, docks, loading racks, and associated piping; and crude and light-product marine terminals. The company also owns crude oil and natural gas gathering systems and pipelines as well as natural gas and NGL processing and fractionation facilities in key U.S. supply basins. More information is available at www.MPLX.com

About WhiteWater

WhiteWater is an Austin-based independent midstream company providing transportation services to domestic oil and gas plays. For more information about WhiteWater, visit www.whitewatermidstream.com.

About Stonepeak Infrastructure Partners

Stonepeak Infrastructure Partners (www.stonepeakpartners.com) is an infrastructure-focused private equity firm with over $15 billion of assets under management and with offices in New York, Houston and Austin. Stonepeak invests in long-lived, hard-asset businesses and projects that provide essential services to customers, and seeks to actively partner with high-quality management teams, facilitate operational improvements, and provide capital for growth initiatives.

About WTG

WTG (West Texas Gas, Inc. & affiliates) is composed of a family of related natural gas midstream and downstream entities headquartered in Midland, TX since 1976 with operations in more than 90 Texas and Oklahoma counties. These WTG entities operate more than 700 MMcf/d of gas processing capacity with more than 10,000 miles of gathering systems, 1,800 miles of transmission pipelines and distribution systems serving approximately 25,000 LDC customers.

This press release contains forward-looking statements within the meaning of the federal securities laws. These forward-looking statements relate to, among other things, statements with respect to forecasts regarding capacity, rates, incremental investment, market conditions and the market and operational opportunities discussed above. You can identify forward-looking statements by words such as "anticipate," "design," "estimate," "expect," "forecast," "plan," "project," "potential," "target," "could," "may," "should," "would," "will" or other similar expressions that convey the uncertainty of future events or outcomes. Such forward-looking statements are not guarantees of future performance and are subject to risks, uncertainties and other factors, some of which are beyond the control of the companies and are difficult to predict. Factors that could impact the opportunities described above are set forth under the heading "Risk Factors" in MPLX's Annual Report on Form 10-K for the year ended Dec. 31, 2020, and Quarterly Reports on Form 10-Q, filed with the Securities and Exchange Commission (SEC). In addition, the forward-looking statements included herein could be affected by general domestic and international economic and political conditions. Unpredictable or unknown factors not discussed here or in MPLX's Form 10-K, Forms 10-Q and other filings with the SEC could also have material adverse effects on forward-looking statements. Any forward-looking statements speak only as of the date of the applicable communication and the companies undertake no obligation to update any forward-looking statements except to the extent required by applicable law. Copies of MPLX's Form 10-K, Forms 10-Q and other SEC filings are available on the SEC's website, MPLX's website at http://ir.mplx.com or by contacting MPLX's Investor Relations office.