At approximately 11:00 PM on Friday, July 1 a break occurred in a 12-inch pipeline owned by ExxonMobil that resulted in a spill of crude oil into the Yellowstone River approximately 20 miles upstream of Billings, Montana. According to the company’s estimates, 1,000 barrels of oil entered the river, which is in flood stage, before the pipeline was cut off.

EPA’s primary concern is protection of human health and the environment, and the agency is conducting both air and water sampling to determine what impacts the spill may have on air or water quality, while also ensuring the responsible party is held accountable. EPA began initial water sampling yesterday and comprehensive air and water sampling plans are being developed.

EPA is also directing and overseeing cleanup activities since arriving at the site. As of Tuesday, July 5, approximately 350 responders are on the scene and conducting cleanup activities. Personnel continue to walk the shores and deploy absorbent boom along the river banks to absorb oil that has collected in slow water areas along the shoreline. Responders continue to work to assess where the oil has traveled and what impact it may be having.

EPA Region 8 Administrator Jim Martin briefed Governor Schweitzer and other state officials on the cleanup operation today and led the group to view on-site response activities.

The river has been divided into 4 divisions for planning and operational purposes. Initial cleanup activities are concentrated in the first two divisions -- from Laurel to Duck Creek Bridge and Duck Creek Bridge to Johnson Lane -- where responders have identified the most oil-impacted areas. The third river segment encompasses the area from Johnson Lane to Miles City and will also undergo reconnaissance and cleanup. The fourth division includes the remaining downstream portion of the river from Miles City to Glendive.

EPA is coordinating its response actions with the Department of the Interior, Fish and Wildlife Service and state and local agencies and will take whatever steps are necessary to ensure ExxonMobil, as the responsible party, addresses any and all potential impacts of this spill.

In addition, the U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration is responsible for determining the cause of the pipeline failure and has been onsite since Saturday.