Federal prosecutors and Colorado health officials on Monday targeted PDC Energy, one of the largest oil and gas drillers along the Front Range, alleging the company has for years violated clean-air laws, hurting people and the environment by leaking volatile chemicals from storage tanks.

A civil lawsuit, filed in federal court in Denver, contends PDC’s pollution helped put Colorado out of compliance with national clean air standards. The lawsuit says PDC illegally emitted volatile organic compounds (VOCs) from tanks north of metro Denver.

VOCs mix into the atmosphere and form ground-level ozone, regulated air pollution for which Colorado could face penalties for failing to meet national clean air standards.

PDC owns or operates about 600 groups of tanks in Adams and Weld counties that the company certified as controlled to meet state air quality requirements. But at least 86 groups of tanks, and potentially hundreds more, violated numerous requirements, the lawsuit said. “PDC’s failure to comply with these requirements has resulted in significant excess VOC emissions, a precursor to ground-level ozone. PDC operates in an area where air quality does not meet the National Ambient Air Quality Standards….for ground-level ozone. PDC’s unlawful emissions contribute to this exceedance of the ozone” standards.

Environmental Protection Agency Administrator Scott Pruitt said federal authorities will work with state agencies to enforce clean air laws.

“Violations of environmental law will be pursued and punished,” Pruitt said in a prepared statement. “We will work with our federal, state and local partners to punish those that violate the laws to the detriment of human health and the environment.”

Reducing air pollution from oil and gas industry tanks is a critical part of Colorado’s work to comply with the ozone standards, CDPHE environmental programs director Martha Rudolph said in a prepared statement. “Colorado has been a leader in developing and implementing control requirements for these tanks and it is vitally important that we take the necessary steps to ensure that these requirements are uniformly followed.”

State air quality commissioners last year put forth a plan to meet an old federal ozone standard — 75 parts per billion, set in 2008 — by relying on existing initiatives to shut coal-fired power plants, enforce controls on the oil and gas industry and shift to cleaner vehicles. But they’ve said it will be 2021 before they meet the current 70 ppb standard set in 2015.

Oil and gas industry groups opposed the plans for reducing ozone emissions.

PDC chief executive Bart Brookman in a statement Monday said his company has been “in continuous discussions” with federal and state authorities for over a year and has “worked diligently to design, maintain and operate our production facilities in compliance with the guidelines of not only the Clean Air Act but all relevant regulations.”

Brookman’s statement added that “we are confident in our ability to work together with all regulatory agencies in coming to an agreeable solution without extended litigation.”