Big Sky Times

The Fish Consumption Advisory Board (FCAB) has updated its advisory for fish consumption from the Yellowstone River. The board, which includes representatives from the Montana Department of Public Health & Human Services (DPHHS), Montana Department of Environmental Quality (DEQ), and Montana Fish, Wildlife & Parks (FWP), has advised women of childbearing age and young children to avoid consuming shorthead redhorse suckers. This recommendation applies to the section of the river from Bratten Fishing Access Site to Itch-Kep-Pe Park in Columbus due to elevated hydrocarbon levels.

Hydrocarbons, which are composed solely of carbon and hydrogen atoms, can vary from simple gases like methane to complex chemicals found in crude oil. They occur naturally and in industrial settings. Although human consumption of shorthead redhorse is uncommon, there are no restrictions on using this fish as bait while fishing for other species.

The advisory follows a series of sampling efforts that began in summer 2023 after a train derailment resulted in liquid asphalt spilling into the river. Polycyclic aromatic hydrocarbons (PAHs) and other hydrocarbons were detected in fish tissue during these samplings, but the contaminant source remains unidentified.

On June 24, 2024, FWP crews collected various fish species at Otter Creek Holmgren Ranch Fishing Access Site and Huntley on the Yellowstone River to monitor potential human health concerns. The sampling included brown trout, rainbow trout, longnose sucker, mountain whitefish at Otter Creek and Holmgren Ranch sites; smallmouth bass, channel catfish, goldeye, and shorthead redhorse were sampled at Huntley.

After averaging results from all sampling efforts between summer 2023 and summer 2024, only shorthead redhorse exceeded recommended hydrocarbon levels for children under six years old and women of childbearing age. Previous advisories for other fish species have been lifted.

Fish movement within river systems complicates determining contaminant sources. The FCAB's sampling aimed to assess human consumption risks rather than identify contamination origins. Currently, no additional sampling is planned for this section of the Yellowstone River.

Research indicates that high consumption over time may affect liver, kidney, and blood functions based on animal studies; however, such effects have not been documented in humans. Most chemicals detected have not been classified as carcinogenic.

For more information about petroleum hydrocarbons, visit CDC's Total Petroleum Hydrocarbons page.