As Colorado Parks and Wildlife continues to assess damages to the North St. Vrain Creek after last week’s gasoline tanker spill, several hundred dead fish have been identified in the past few days.

The gasoline tanker rolled April 27 on Highway 36 between Lyons and Estes Park. It was hauling 8,000 gallons of gasoline, with 500 to 1,000 gallons spilling into the environment, according to the Environmental Protection Agency.

The EPA said an unknown amount of the spilled gasoline drained into the North St. Vrain Creek, resulting in the fish kill.

Several fish killed after tanker crashes, spills up to 1,000 gallons of gas near Lyons

The EPA is working to clean the gasoline as CPW assesses the extent of the fish kill. In large incidents such as this, counting every dead fish is not possible, but there are statistically valid methods to accurately estimate the losses, CPW said.

CPW researchers Mindi May and Pete Cadmus collected macroinvertebrate samples, took water quality measurements, measured algae and surveyed for fish Saturday.

“We visited numerous sites on the river from just upstream of the crash site all the way down to the confluence with the South Saint Vrain,” May said.

Additional updates will be released by CPW as the river is analyzed. The EPA, the Colorado Department of Public Health and Environment and the Colorado State Patrol are assisting CPW in collecting information.

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Anyone with photos or videos of dead fish, or who collected and saved dead fish, is asked to contact CPW at [email protected]. It is not legal for citizens to transport live fish.

According to the Colorado State Patrol, the tanker driver’s speed is being investigated as a possible factor in the crash. The driver was hospitalized with minor injuries and is expected to be OK.

The water supply for Lyons and Longmont was diverted at the Longmont Dam and has not been impacted, city officials said.