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Groups: DEQ not doing enough on ‘unlawful’ gas-field discharges

A worker takes a water sample from an outfall at the Moneta Divide Field. (DEQ)

Conservationists find troubling water samples, want permit review after DEQ eased testing requirements for Moneta Divide pollution

By Angus M. Thuermer Jr., WyoFile

Three conservation groups are criticizing the Wyoming Department of Environmental Quality for allowing polluting flows to continue at a Fremont County gas- and oilfield and have asked the state agency to reconsider its permit.

DEQ should re-open its review of Aethon Energy’s permit at the Moneta Divide field, modify it and “ramp-up” enforcement of existing violations to meet the agency’s obligations under the Clean Water Act, the groups wrote in a March 17 letter. The Powder River Basin Resource Council, Wyoming Outdoor Council and Natural Resources Defense Council made the request after the DEQ modified the pollution permit for the field, which Aethon and Burlington Resources are expanding from roughly 800 to 4,250 wells, most of them gas wells.

“We remain concerned that DEQ is simply not doing enough to correct longstanding significant water quality violations, resulting in the continuation of unlawful discharges of pollution,” the groups said.

Why it matters

Aethon’s discharges of polluted “produced” water pumped from wells flow into Alkali and Badwater Creeks above Boysen Reservoir. The protected Wind River flows from the reservoir’s Boysen Dam. Thermopolis gets drinking water from the waterway about 23 miles below the dam.

The groups wrote that pollution from the field shows the water failed standard toxicity tests on flathead minnows and water fleas. The groups ask that the agency increase the frequency of those tests.

Elevated chloride concentrations also worry the groups, who say that brine harms freshwater aquatic life and has “likely contributed to severe adverse impact” to Alkali Creek.


Aethon has struggled to find an adequate method of disposing of millions of gallons of tainted water a day and thousands of tons of pollutants a month. DEQ rejected the company’s application to let the pollutants flow into Boysen Reservoir where it would be diluted. In 2020 DEQ issued a permit requiring monitoring and significant reduction of salinity by 2024.

Aethon reported in early 2021 and twice thereafter that discharges exceeded limits set in that 2020 permit. DEQ then made a “major modification” to that permit, removing or increasing some of the limits, ending some periodic sampling and moving some sampling locations. The agency contended sampling results justified the changes.

That modification prompted the groups’ recent appeal.

Who said what

DEQ should penalize Moneta operators for repeated failures to meet the toxicity test standards, the groups’ letter states. It also should accelerate a plan to reduce the salinity of discharged water by making Aethon re-start the water-cleansing Neptune plant that the company had shut down.

“High concentrations” of Benzene and Toluene found in samples appear to violate DEQ rules and regulations, the letter states. Neither DEQ nor Aethon responded to messages seeking comment by publication deadline.



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