Haul trucks with the Cripple Creek and Victor Gold Mining Company carry ore on April 13, 2021, at one of the company's mining operations south of Cripple Creek. A fully loaded haul truck can carry 250 tons of gold ore. (Mark Reis, Special to The Colorado Sun)

Colorado air quality regulators are moving to tighten oversight of small sources of air pollution, which critics contend have gotten a free pass under the previous policies of the state Air Pollution Control Division.

Those policies were the target of a federal whistleblower complaint by division employees and an investigation by the state’s Attorney General’s Office, and led to a shake-up at the division.

Under the division’s interim guidance, any operation seeking an air emissions permit that may release the equivalent of a little under half a pound of sulfur dioxide or nitrogen oxides an hour or 11 pounds of fine particulates a day will have to undergo a modeling review.

Modeling is used to assess the scale of the emissions and could lead to permit requirements for pollution controls or changes in operations.

“It is definitely a positive step to see them moving to address sources that they were ignoring,” said Rebecca Curry, a policy advocate with the environmental law group Earthjustice. “While minor sources viewed individually may seem small, together they are a really significant contributor to the Front Range’s ozone problem.”

The Front Range suffered its worst ozone season in recent history, with 73 ozone alert days. The region is set to be downgraded from a “serious” to a “severe” nonattainment area by the federal Environmental Protection Agency, requiring more pollution curbs.

The whistleblower complaint, still pending with the EPA’s Office Inspector General, covers several issues, including the question of whether small emission sources were getting an adequate review.

The complaint cited a 2010 memo that exempted any source – such as a factory or trucking terminal – that emitted less than 40 tons a year of sulfur dioxide or nitrogen oxides – from having to show they also complied with the tighter one-hour standards.

The three state employees who filed the complaint said that amounted to unlawfully issuing permits.

An independent investigation of the issues released in September, by Attorney General Phil Weiser, found that while division policies were “inadequate,” part of the problem came from a lack of guidance from the EPA on minor sources and modeling.

The report did criticize Garry Kaufman, the division director, for failing to disclose a conflict of interest involving a Teller County gold mine seeking air permits he had previously represented in his private law practice.

Early this month, Kaufman moved from the air division to the newly created job of deputy director of regulatory affairs.

The interim guidance will be reviewed by an expert panel and open for public comment before a final policy is set early next year, said Shaun McGrath, the Colorado Department of Public Health and Environment’s director of environmental programs.

“They will look at the recent independent investigation … and look at modeling practices in other states and come back with recommendations and changes we might make before we go ahead with final guidance,” McGrath said.

One of the issues raised in the critique of the air division’s minor-source policy is that while short-term air emissions may not have an overall impact on ozone pollution, which is created when sulfur dioxide, nitrogen oxides and volatile organic chemicals bake in the sun, they could have adverse local impacts.

Under the interim guidance, modeling may be required, even when it is under the threshold, if the area has poor dispersion of pollution, if it is located in complex terrain, is located near other sources of pollution, such as fugitive emissions, or already has poor air quality.

“We are encouraged that CDPHE is developing guidance that includes the expertise of their modeling staff,” Chandra Rosenthal, head of the Rocky Mountain PEER Council, said in an email. “However, in the current draft there are a couple of provisions that are backdoor exits for industry.”

For example, an applicant can opt out of the modeling review by implementing a plan to monitor emissions to show it is in compliance, Rosenthal said. “It is allowing the construction to go forward and hoping that it will not exceed standards with after-the-fact monitoring.”

McGrath said the “monitoring option is not an easy way out … a source has to submit a monitoring plan that is rigorous and state approved.”

Rosenthal also said that giving priority to areas with poor air quality is a good step, but noted the guidance is for areas with “poor existing air quality.”

“That sounds great, but the clause defines that as monitored air quality,” Rosenthal said. “The problem is that the state is not covered with air monitors.”

Special to The Colorado Sun Twitter: @bymarkjaffe