Malathion Spill Investigation Reveals More Details
Spill most likely came from a permitted aircraft, says DA
by Joy Ufford

In the past week, an investigation by the Wyoming Department of Agriculture (DA) into a malathion spill that occurred July 24 or 25 on the Green River near Daniel has gathered some mored etails.

Lab tests confirmed last week that the contaminant that killed hundreds of whitefish and brown trout was malathion, according to Hank Uhden, manager of the DA’s technical services division.

Investigators have gathered more information from letters and interviews and reached several conclusions, Uhden said this week.

“We had operating theories,” he said, explaining that a theory that the spill was dumped by a truck was discarded because there were no tracks anywhere near the scene. “With a degree of certainty itwas probably an aircraft but it also appears not all of (the malathion) went intothe river.”

Malathion was also found in additional soil samples taken from the riverbank and tested in the DA labs, he confirmed.

“In the soil samples we collected it is very low, a very low concentration,” he said. “It is breaking down quickly.” There is also “a degree of certainty” on the maximum amount that could have been spilled but Uhden isn’t talking, citing factors such as the plane’s altitude, speed, type of aircraft, size of ‘dump” and how quickly the product was evacuated.

Because the DA licenses and registers commercial use of pesticide products the agency was trying to determine the “who, when and how” of the incident, he added. Uhden said there is “pretty strong evidence” that the malathion spill was made by someone permitted to be spraying the insecticide. “Yes,” he confirmed. “The likelihood of evidence is pointing us in a specific direction. We do know malathion was being used (for mosquito abatement) up there.” Whether the spill was an accident or deliberate act, Uhden was unprepared to say.

“At this point that is undetermined,” he said. “We don’t have the answers to that.” However, the spill went unreported so that will be taken into account, accident or not, Uhden said. Wyoming Game and Fish (G&F) officials didn’t learn of the spill until several days later when a fisherman came into the Pinedale office. G&F was the first agency on the scene, followed by the state Department of Environmental Quality and then the DA.

Uhden hopes to have the investigation completed within the next two weeks and will thenmeet the state attorney general and find out whether prosecution is advised. On first offenses, state statutes allow a penalty of up to $500 in fines or a year in a county jail, he said.

When the investigation is complete, Uhden said, his office will issue a press release to let the public know ‘some level of conclusion has been brought to it.”