BILLINGS — Laboratory analysis of fish collected in the Yellowstone River below the site of a July 1 oil spill show no detectible petroleum in consumable fillet tissues. Traces of petroleum hydrocarbons found in reproductive and digestive organs leave questions about the long-term health of the fish, however.
Crude oil spilled into the river when ExxonMobil Pipeline Co.’s 12-inch Silvertip Pipeline broke beneath the flooding Yellowstone River near Laurel. Oil pollution in varying quantities has been detected on the river’s bed, shores, debris, vegetation and islands downstream as far as the confluence with the Bighorn River near Custer. Cleanup is ongoing.
The oil spill prompted a July advisory against eating fish caught the Yellowstone River between Park City and Custer, pending laboratory tests.
In July Montana Fish, Wildlife and Parks biologists collected long-nose suckers, rainbow trout and smallmouth bass between Laurel and Billings and below the Huntley Diversion Dam. Fillet tissue, gonads and livers from the fish were sent to a laboratory for analysis.
Fillet tissues were tested to reflect any effect on human health from fish consumption. Reproductive and digestive organs were tested to help measure any cumulative, long-term health effects on fish.
Laboratory results released this week show no detectable hydrocarbons – or oil residues – in any of the fish fillet samples. Trace amounts of hydrocarbons were found in the organs of some long-nose suckers.
Additional information about the oil spill is available online from the State of Montana at www.yellowstoneriveroilspill.mt.gov.