Colorado regulators voted Thursday to proceed with setting new emissions-control rules for priority toxic air contaminants but stopped short of linking them to permit requirements for now, choosing instead to focus on other ways to reduce five key pollutants.
Members of the Colorado Air Quality Control Commission agreed to hold a rulemaking hearing at their April meeting to establish controls for benzene, formaldehyde, hydrogen sulfide, ethylene oxide and hexavalent chromium compounds. The rules will affect about 300 facilities emitting the pollutants above thresholds that the Colorado Air Pollution Control Division has proposed, ranging from oil-and-gas rigs to medical-device factories to wastewater treatment plants.
The rulemaking will be the next step in a years-long process, beginning with the passage of a 2022 law, in which air-quality regulators have expanded their focus from greenhouse-gas emissions to co-pollutants that increase risks of cancer and other diseases. AQCC members singled out the five priority pollutants in January, established health-based standards in September that define when their concentration can be harmful to humans and, come April, will take the definitive steps to make emitters rein them in.
Who will the rules on toxic air contaminants impact?
Companies who will come under the regulations will be those who emit the pollutants above a certain threshold — 10,000 pounds a year of hydrogen sulfide, 4,000 pounds annually for benzene and formaldehyde and any amount of hexavalent chromium. Because the federal government enacted new regulations last year for ethylene oxide, which is emitted from plants that sterilize medical equipment, the state largely will follow those guidelines in regulating three device factories, including Terumo BCT in Lakewood.
But in order to harness limited state resources, the APCD has recommended focusing enforcement on certain geographic areas. Priority would go to facilities within poorer and typically more minority-populated disproportionately impacted communities, as well as those within one mile of a census block with modeled combined cancer risks from all priority TACs of at least 20 excess cases per million people.
Control strategies would vary from pollutant to pollutant but would involve requirements to modify production processes, add control technologies and substitute less-toxic materials, said Amanda Damweber, a supervisor with APCD’s planning and policy program. The division must submit an air-toxics permitting conceptual framework and needs assessment report to the General Assembly by the end of 2025, but it can’t proceed with permitting regulations unless legislators choose to run what would be a controversial bill.
That’s not to say some of the control strategies that the AQCC could approve in April would not be strict, even if Damweber emphasized Thursday that any new rules must be technically and economically feasible.
How the pollutants will be limited
The proposed rules, for example, would outlaw any new operations from using baths of hexavalent chromium to prevent corrosion and wear on metals like classic car bumpers. And they would ratchet down limits on formaldehyde emissions from spark ignition engines and gas-fired turbines, 95% of which are in the oil-and-gas sector and have prompted groups like the Colorado Oil & Gas Association to question if the rules are feasible.
But in unveiling their plan on Thursday, APCD leaders also offered several changes from earlier drafts that are likely to produce a sigh of relief from some companies.
The proposed rules, for example, would exempt upstream and midstream oil-and-gas facilities from having to meet the new benzene limits because state regulations already require them to reduce volatile organic compounds and greenhouse-gas emissions. Those requirements will, in turn, reduce benzene emissions, Damweber told the AQCC, and the exemption would allow APCD to focus on emitters that are less regulated.
Also, wastewater-treatment plants, which emit hydrogen sulfide, would be required under the rules only to submit reports listing their emissions if they reach certain thresholds — reports that state officials can analyze for potential future action. While some municipal leaders argued their systems should be exempted from any rules, northeast Denver-area residents living near Metro Water Recovery facilities had asked for stronger regulations on the pollutant that can cause headaches, nausea and psychological disorders.
Scrutiny of some exemptions
In public comments offered Wednesday to the AQCC, Tehya Stockman, air-quality control specialist for Adams County, noted with disappointment that Metro Water Recovery faced no discernible controls through the rules. And she and several other speakers lamented that the Suncor Energy USA refinery in Commerce City is impacted only by proposed benzene requirements to lower the volatile-organic-compound detection limit for leak detection and radar equipment in order to get leaks detected and repaired more quickly.
“I think part of the challenge with this rulemaking is the things that are excluded are important, as are the things that are included,” said AQCC member Jana Millford, expressing concern over whether existing regulations on oil-and-gas extraction will really reduce benzene levels if those facilities are exempted from the new rules.
Impacted businesses — which also include manufacturing plants using formaldehyde-emitting furnaces and biogas facilities generating both energy and hydrogen sulfide from mammal waste — now have five months to determine what the rules will mean. And likewise, environmental advocates can formulate arguments on whether the plan does enough to prevent the health problems more prevalent to certain communities.