EPA ID# IDD055030852
EPA Region 10
Bannock County

2nd Congressional District

Other Names:
Last Update: May, 2010

Hide details for Site DescriptionSite Description

The Union Pacific Railroad Co. (UPRR) Sludge Pit site covers about one acre in Pocatello, Idaho. From 1961 until 1983, UPRR dumped approximately 2,500 yards of sludge from its wastewater treatment plant into a one-acre unlined sludge pit. In 1983, EPA found that seepage from UPRR's sludge pit, and from an area in the vicinity of the sludge pit where a tie treating facility was located, were contributing to upper aquifer, and, to some extent, lower aquifer groundwater contamination. The McCarty/Pacific Hide & Fur site, another NPL site, is located approximately 300 yards from the pit. Approximately 45,000 people live within four miles of the site, but the immediate area is very sparsely populated. Private and municipal wells are located within a mile of the site. Private wells in the area draw from the lower aquifer. The municipal wells for the city of Pocatello are located within three miles of the site.

Site Responsibility: This site has been addressed through Federal and potentially responsible parties' actions.

NPL Listing HistoryDates
Proposed Date:09/08/1983
Removed Date:
Withdrawal Date:
Final Date:09/21/1984
Deleted Date:09/22/1997

Hide details for Threats and ContaminantsThreats and Contaminants

Media Affected: Groundwater, Soil & Sludges
Samples from private drinking water wells from the lower aquifer contained low levels of organic compounds consistent with the wastes discharged into the pit, which were below EPA drinking water standards. The greatest threat to groundwater was the migration of contaminants from the upper aquifer to the lower aquifer. The sludge/soil material in the pit area was contaminated with heavy metals, polycyclic aromatic hydrocarbons (PAHs), and organic compounds. The potential health threats of greatest concern were from drinking contaminated groundwater and ingesting sludge from the pit. Studies also confirmed that runoff from the site did not flow from the sludge pit into the nearby Portneuf River.

Hide details for Cleanup ProgressCleanup Progress

Cleanup activities were performed by Union Pacific under a Consent Decree with EPA. The remedy was completed in 1994, and consisted of the excavation and off-site disposal of 13,821 tons of sludge/soil into a RCRA-permitted landfill, and pre-treatment of over 62 million gallons of groundwater before discharge to the city water treatment plant. Quarterly groundwater monitoring since the cleanup was completed confirmed that groundwater beneath the site now meets the Federal Drinking Water Standards. EPA deleted the site from the NPL in September 1997.

Hide details for Regional ContactsRegional Contacts

SITE MANAGER(S):Deb Yamamoto
E-MAIL ADDRESS:yamamoto.deb@epa.gov
PHONE NUMBER:206-553-7216
Information pertaining to this site is housed at the following location(s):
Pocatello Public Library (Administrative Records)
113 South Garfield
Pocatello, ID 83204