Region 8
EPA response to Sand Creek Seep
UPDATE
December 6, 2011
EPA continues to respond to a seep of a gasoline-type material into Sand Creek near its confluence with the South Platte River in Commerce City, Colorado. As of December 6, approximately 3,500 gallons of gasoline-type material has been recovered during the operation, and the isolated area of Sand Creek where the seep is occurring has been largely contained.
A 220-foot interceptor trench was completed on December 3 between the seep and the creek to prevent additional material from entering Sand Creek. This trench appears to be effective in containing and collecting residual seeping material. Current information indicates that the material is migrating from the Suncor refinery, traveling under the Metro Wastewater Treatment Facility and appearing on the shore of Sand Creek.
There continues to be no evidence or reports of impacts to downstream water users of the South Platte River or to wildlife in the affected area. Initial results from samples collected from in impacted areas along Sand Creek from Tuesday, November 29 through Friday, December 2 confirm the presence of benzene as well as toluene, ethlylbenzene and xylene. EPA believes benzene concentrations are largely a result of the disturbance from cleanup crews working in and near the river at the seep location and expects levels will fluctuate as cleanup actions continue. The cold temperature also reduces the evaporation rate of contaminants, which may be a factor in day-to-day fluctuations. We expect these levels will decrease once we complete the removal of material from a sandbar and other residual material between the trench and Sand Creek.
Summary of EPA Surface Water Sampling Results (PDF, 4 pp, 498K)
Background
On November 28, EPA was notified of a sheen and associated gasoline-type odor reported by a fisherman on Sand Creek. EPA responders quickly deployed to the site and identified a stretch of the stream bank where a gasoline-like material was seeping into the stream. EPA contacted Suncor, owner of a refinery adjacent to the creek, and requested that they initiate a response.
Suncor response teams and contractors immediately deployed containment and absorbent booms throughout the stream and worked overnight to create an earthen and sandbag dam around the shoreline area where the gasoline-like material was seeping. The dam has successfully contained nearly all of the material seeping from the shoreline. Containment and absorbent booms are still deployed in several locations downstream of the seep to ensure any residual material that is not contained by the dam is collected and recovered. Material is being vacuumed off into trucks as it accumulates. Suncor is also monitoring air quality at the site.
Suncor has taken response actions to capture material and prevent the flow of material into the creek. This includes damming the shoreline of Sand Creek where material is seeping and constructing an interceptor trench that is expected to act as a barrier to stop the flow of material into the creek. Suncor and the Colorado Department of Public Health and Environment (CDPHE) are continuing to investigate the source of contamination. EPA will continue its oversight of response actions as Suncor continues to implement the cleanup.
Below: image of seep location and boom material in Sand Creek, December 1
