Celtor Chemical Works is a 26-acre former sulfide ore mill on the Hoopa Valley Indian Reservation in Hoopa, California. It operated from 1960 to 1962, leaving acidic runoff and elevated metals in soil throughout the site. EPA added it to the National Priorities List (NPL) in 1983 and deleted it in 2003 after an initial cleanup removed over 2,500 cubic yards of contaminated material. In 2016, additional mine tailings were discovered, triggering a new investigation starting in 2017.
The site has nine contaminants of concern. Lead and arsenic pose direct human health risks and were found in soil across the site. Lead can cause behavioral problems, learning disabilities, and seizures, with children being especially vulnerable. Arsenic is a known human carcinogen. Cadmium, copper, sulfuric acid, and zinc were also detected in soil and in solid waste from ongoing maintenance work. Other metals including cadmium, mercury, and zinc are being assessed for ecological risks.
The main exposure route is touching contaminated material and accidentally swallowing it. EPA found evidence that children were playing directly in the mine tailings. During summer 2023, EPA completed a removal action that excavated about 2,500 tons of contaminated mine waste and disposed of it off-site. The excavated area was backfilled with clean river rock and gravel and replanted with native species. After that work, the site achieved Human Exposure Under Control status. Residual contaminated material remains buried at the site but does not currently pose a risk to the community. EPA conducts annual inspections after the rainy season to check for newly exposed material and is evaluating options for the remaining contamination. The site is not yet ready for anticipated reuse across the whole property.
The site is divided into three operable units. Cleanup for the third unit, covering post-remedial activities, is still in progress. A feasibility study for that unit began in April 2023, with remedial action estimated to wrap up between September and November 2028.
Tribal members can get involved through the Hoopa Valley Tribal Environmental Protection Agency (TEPA), which has participated in the cleanup since 2020 with support from an EPA grant. TEPA has an independent technical consultant who advises the tribe and assists with field sampling. Community members can reach TEPA at 530-625-5515 or at hoopaland.org. Public records about the cleanup are available at the Kim Yerton Memorial Library at 370 Loop Road and at the Hoopa Tribal Environmental Protection Agency at 12 Cannery Road, open Monday through Friday from 8:30 a.m. to 5:00 p.m.
