After an energy company at the troubled Moneta Divide gas- and oilfield discharged more pollution than allowed under a 2020 permit, Wyoming is poised to change that permit to remove limits on, and monitoring of, some waste flows.

The state Department of Environmental Quality is set to relax oil and gas well wastewater discharge limits and monitoring requirements at the Moneta Divide Field near Shoshoni, a “statement of basis” for the draft permit states. DEQ is proposing a “major modification” to a permit issued a little more than a year ago to Aethon Energy Operating LLC.

DEQ would remove effluent limits on and sampling requirements for radium, barium and zinc flowing from the field into Boysen Reservoir and the Wind and Bighorn rivers. It would end routine testing requirements for a host of other compounds: aluminum, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver and thallium.

If approved, the DEQ would make other changes to the October 2020 permit, including screening to better detect fracking fluids. Those fluids, many of them toxic and necessary to develop oil and gas wells, are not allowed to be discharged along with naturally occurring underground “produced water.”

A coalition of conservation groups is challenging the changes. 

“Neither Aethon nor DEQ has justified removal of radium from monitoring and sampling requirements,” three groups wrote in a statement. “We continue to oppose discharges that fail to protect aquatic life as required by Wyoming’s water quality standards and threaten drinking water supplies.”

DEQ proposed the modification after Aethon applied for changes based on new information it submitted. The waste and pollution initially flows into an unnamed drainage, on to Alkali Creek, Badwater Creek and then to Boysen Reservoir and the protected Class I Wind River downstream of Boysen State Park.

The 2020 permit was the focus of considerable debate when proposed in 2019 by Aethon and Burlington Resources. Public comment, including some made at well-attended public hearings, caused the DEQ to radically change the proposal.

Aethon and Burlington had sought to dump millions of gallons of tainted water a day and thousands of tons of pollutants a month onto the landscape as part of a plan to add 4,205 new wells to the longstanding field. DEQ required the companies — by 2024 — to greatly limit the amount of salty water they could spew and set a suite of monitoring requirements.

Aethon reported in early 2021 and twice thereafter that discharges from the Frenchie Draw wastewater treatment plant at Moneta exceeded limits set in that 2020 permit. Aethon now wants some of those limits increased or removed, some of the sampling locations moved downstream and some periodic sampling to end.

DEQ accepted comments on the proposal through Nov. 15 and received four, agency spokesman Keith Guille said in an email. One, from conservationists, questioned the proposal and requested, unsuccessfully, a longer comment period because of the complex nature of the subject.

“Additional revisions — some mandated by law and others within the discretion of the WDEQ — are needed to safeguard Boysen Reservoir and its tributaries from the impacts of oil field wastewater,” the Powder River Basin Resource Council, Wyoming Outdoor Council and Natural Resources Defense Council wrote. The reservoir — 40 miles from gas- and oilfield discharges — supplies drinking water to the town of Thermopolis through the protected Wind River and, farther downstream, the Bighorn River.

New information submitted by Aethon justifies the changes to the permit, the DEQ said. Further, “the net effluent output at the facility remains unchanged,” regulators wrote.

“The proposed [new] permits contain limitations and conditions that will assure that the state’s surface water quality will be protected,” according to the DEQ.

Monitoring that DEQ required Aethon to conduct starting in 2020 revealed that the Frenchie Draw gas production treatment facility, which separates gas from briny, produced water, exceeded permit limits several times. The Powder River Basin Resource Council obtained Aethon’s report and others through a public records request and shared them with WyoFile.

On Feb. 1 this year, for example, Aethon found radium registering up to 8.8 picoCuries a liter at one discharge point where DEQ had set a limit of 5 pCi/L for the radioactive substance. Five pCi/L is the maximum federal drinking water standard, above which the element may cause health problems.

DEQ set the 2020 limit to ensure conditions allow “aquatic life, livestock and wildlife watering, secondary recreation, industry, scenic value[s]” to continue in Alkali Creek. Aethon, however, contends that regulations allow the radium limit at Alkali to be 60 pCi/L.

Aethon wrote the DEQ in February the level of the discharge should be increased from 5 pCi/L to 60 pCi/L for radium and should be measured farther downstream from the discharge point — at Alkali Creek itself. DEQ now proposes a major permit modification that would remove radium limits and end sampling requirements “based on site-specific effluent data collected within and below the facility.”

Aethon made similar arguments for barium after finding 3,460 micrograms per liter of it at a discharge point. DEQ had set a limit of 2,000 ug/L for the discharge point in 2020.

DEQ would end sampling requirements for the other suite of constituents — aluminum, arsenic and others listed above, after Aethon sampling revealed “no reasonable potential” to exceed water quality standards.

Instead of less monitoring, the conservation groups argued for additional in-stream testing, continued sampling and reporting “to address fisheries and aquatic life concerns.

“Wyoming water quality standards prohibit the presence of ‘radioactive materials attributable or influenced by the activities of man’ in all Wyoming surface waters or in the sediments ‘in amounts which could cause harmful accumulations of radioactivity in plant, wildlife, livestock or aquatic life,’” the letter from PRBRC, WOC and NRDC reads. WDEQ should not reward exceedance of permit limits with removal of the limits, the groups contend.

“Aethon misunderstands the criteria applicable to effluent limitations,” the groups wrote. “The classification of the water body into which the discharge occurs [one of the bases on which the permit changes are sought] is one factor in setting applicable permit limits — but it is not the only factor.”

The groups also called for monitoring of BTEX — benzene, toluene, ethylbenzene and xylene — dangerous volatile organic compounds that vaporize easily. And they want a clean-up plan to correct existing degradation caused by “decades of oilfield pollutants,” according to their nine-page comment letter.

DEQ does not have a timeline for approval of the permit, spokesman Guille said.

“We’re currently in the process of responding to comments on this modification, and the commenting parties will receive a written response from us when a final action is taken by DEQ on the permit modification,” he wrote. The department would not comment on the conservationists’ letter, he said, but would eventually respond to them in writing.

Aethon declined requests for comment.