Pittsburgh, PA – The Pennsylvania Department of Environmental Protection (DEP), has entered into a Consent Order and Agreement (COA) with United States Steel Corporation (U.S. Steel) to address repeated oil sheening discharges from the company’s Mon Valley Works Irvin Plant in West Mifflin, Allegheny County.
“Protecting the waters of the Commonwealth is one of DEP’s core responsibilities,” said DEP Secretary Jessica Shirley. “This agreement ensures that U.S. Steel takes concrete, enforceable steps to prevent further pollution of the Monongahela River.”
Under the terms of the COA, U.S. Steel will pay a $135,000 civil penalty for past violations and implement comprehensive corrective actions, including an outfall monitoring program, an investigation into oil and grease sources, and a mitigation plan designed to eliminate remaining sheens.
The agreement holds U.S. Steel accountable for violations of Pennsylvania’s Clean Streams Law and establishes a detailed framework to eliminate future unauthorized discharges to the Monongahela River.
Between August 2022 and April 2025, DEP investigated at least seven separate complaints of oil sheens discharging from the Irvin Plant’s outfalls into the Monongahela River. DEP inspections confirmed repeated unauthorized discharges of wastewater contaminated with oil from Outfalls 001 and 003, causing visible sheens that, in some cases, extended more than a mile downstream.
In October 2023, DEP issued a Compliance Order requiring U.S. Steel to install containment booms and absorbent materials, as well as to investigate the source of the ongoing sheening events. Despite these measures, subsequent inspections in 2024 and 2025 documented continued violations.
The COA requires U.S. Steel to take immediate and long-term corrective actions to prevent future violations, including:
- Inspection and Maintenance Requirements: Maintain hard booms at Outfalls 001 and 003; conduct daily inspections, including via live-feed cameras; and perform weekly boat inspections until permanent monitoring systems are in place.
- Outfall Monitoring Plan: Submit a detailed plan for DEP review within 90 days, including installation of live video monitoring equipment, Remote Optical Watchers for oil detection, and upgraded containment systems at outfalls.
- Oil and Grease Source Investigation: Complete a facility-wide investigation within three months to identify sources of oil and grease, inspect stormwater conveyances, and evaluate the installation of oil separators.
- Mitigation Plan and Elimination Schedule: Implement an approved mitigation plan and, if any sheens persist within 12 months of completion, submit an additional plan to eliminate all remaining discharges.
U.S. Steel must also submit quarterly progress reports to DEP outlining compliance efforts, inspection results, and corrective actions taken.
In addition to the $135,000 civil penalty, the COA establishes stipulated penalties for any future violations. U.S. Steel must pay fines of $1,000 per day for failing to meet COA deadlines and $7,500 per day for each future sheen observed after the mitigation plan is completed.
The Monongahela River is classified as a warm-water fishery and serves as an important regional waterway for recreation and the support of aquatic life. DEP’s action follows multiple citizen complaints and reflects DEP’s commitment to responding promptly and decisively to pollution events that impact public waters.
The COA remains in effect until DEP determines that U.S. Steel has completed all required corrective actions, and that the facility is in full compliance with state law.
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