CASPER — Joel Bousman wasn’t sure if ozone would be a problem Friday, despite a warning from the state. The snow covered the sage brush and the wind was less than 10 miles per hour — both bad signs. On the other hand, it had been overcast most of the day at the Sublette County commissioner’s ranch near Boulder — a small community about 12 miles southeast of Pinedale, within view of the Wind River Mountains.

You need the right mix of factors to create ground-level ozone: sunlight, snow cover, little to no wind and, of course, emissions from the oil and gas industry — which arrived in force more than a decade ago in the Jonah and Pinedale gas field.

And this year the factors have been right more often than usual.

Friday was the 12th ozone action day of the season — a warning system from the Wyoming Department of Environmental Quality that forces industry to pull back when conditions for ozone are expected. It’s a record number for recent years, and another action day was forecast for Saturday.

But there’s something more troubling in the case of the Boulder area: ground-level ozone is regularly forming despite precautions. Breathing it in can cause a variety of health problems, from chest pain to reduced lung function.

For reasons still unclear to state regulators, in one corner of the Upper Green, the rules and regulations that reversed an air quality crisis more than a decade ago haven’t been enough.

“We don’t have all the answers, yet,” said Keith Guille, spokesman for the state Department of Environmental Quality. “It’s definitely not being ignored. We understand that the public is concerned, as we are.”

The Upper Green River Basin is a bowl-shaped area wedged between the Wind River and Wyoming ranges. That landscape holds bad air in place when there is no wind.

Snowy and sunny years are worse for ozone action days, as was the case in 2017, the last year that ozone action days were a regular occurrence. There was nearly three times the amount of precipitation during the 2017 winter ozone season compared to historical averages, according to a fact sheet from the Wyoming Department of Environmental Quality.

But the controllable factor, and the one that once precipitated the great ground level ozone crisis in the basin, is oil and gas.

More than a decade ago, oil and gas activity degraded air quality to the point it was comparable to Los Angeles, and it changed the way Wyoming regulated industry in the basin, its pipes and compressor stations, trucks and holding tanks. Those regulations have been effective in driving down emissions. The rules are some of the strongest in the country and have inspired attempts by the Environmental Protection Agency and the Bureau of Land Management to institute similar rules across federal and Native American land — though in both cases the Trump administration has recently pulled back on some of those standards. In addition to the ozone action days, Upper Green rules cover the use of equipment to track leaks and regular checks of infrastructure for damage.

And during ozone season, in late winter and early spring, action days are an important part of how the Upper Green manages emissions. In the mix of ozone contributing factors, oil and gas emissions are the one thing regulators can pull back to try and keep ozone at bay. Action days are declared by the Wyoming Department of Environmental Quality as having the potential to create ground-level ozone. Operators in the Upper Green respond by following contingency plans to reduce emissions, such as reducing refueling and cutting truck idling.

This year industry has had to scale back over and over.

Jonah Energy, which operates in a different area of the basin from where the Boulder exceedances have been happening, has scaled back its operations considerably due to action days this year, said Paul Ulrich, spokesman for the oil and gas firm.

“Small stuff. We’re turning off air heaters on pads during the day. Big stuff, shutting down workover rigs,” Ulrich said. “Those have immediate production, operational and financial impacts that we are bearing.”

Jonah has demobilized its completion crew — holding off on finishing wells and bringing them online until mid-April and it is delaying blowing down wells, he said.

“I will tell you though, we plan for it. We train for it and we understand that we have an obligation to do everything we possibly can,” Ulrich added.

The outcome of those actions is evidenced in the lack of ozone exceedances, over an eight-hour period, this year near Jonah’s operations, he said.

But the rules and practices of today may not be enough, if ozone is still forming in the Upper Green, according to the DEQ.

“In 2019, we feel whether or not you have a snow pack or not, we don’t want to see those levels above the standard,” said Guille, of the Department of Environmental Quality.

Nancy Vehr, administrator of the Air Quality Division of the Wyoming Department of Environmental Quality, said she began reaching out to operators in the Boulder area, where more than 30 companies — mostly oil and gas firms — work, when the ozone spike began about two weeks ago. She asked them to find more ways to voluntarily cut emissions.

And they did. But what’s been unique about the Boulder problem this year is that the elevated ozone levels have been persistent, Vehr noted.

“We’ve never had an eight-day stretch in one location,” she said.

But that area has been a problem in the past. Whether it’s temperature or other factors, the Boulder monitor often picks up more air quality concerns than others across the basin, she said.

Ulrich of Jonah said the ozone spikes of this year are a mystery, but it does appear to be isolated and not reflected across the basin, he explained.

“The challenge for this particular season is it’s been one monitoring station,” he said. “From a scientific standpoint, that’s a very new challenge for us all, to fully understand between operators and DEQ and others what’s going on at that station.”

Everyone is going to have to come back to the table, Ulrich said.

“We know we need to take a hard look at it after this year,” he said.

Vehr echoed that confidence in current rules, noting that it would be easier to look back over the data in retrospect and analyze patterns.

When air quality was at its worst in the Upper Green, you could see it like an orange haze, said Bousman of Boulder. Despite the exceedances this year, the rancher said he hadn’t noticed the air quality being any different. Like everyone else, he wondered what was going on at the Boulder monitor, whether it was working properly and how much of the ozone problem was natural. There is deeper snow up that way, he said.

Still, the spikes in safe levels had caught everyone’s attention in the Upper Green, even though they’ve been addressing ozone since 2005 or 2006.

“I think, collectively, we thought we were on top of it, so to speak,” Bousman said. “Now, I’m not so sure.”