Suncor Energy settled a lawsuit with the Colorado Department of Public Health and Environment for $10.5 million in fines and mandated improvements at its Commerce City refinery for a series of air pollution emissions events from 2019 to 2021.

The settlement is the largest in Colorado history for air pollution violations.

In a news release, CDPHE said Suncor will be required to double its fenceline air quality monitoring system and improve its operations to prevent excessive emissions of sulfur dioxide, carbon monoxide, nitrogen oxides, hydrogen sulfide concentration limits and violating opacity and visible emissions standards.

“Under the terms of the settlement, Suncor has agreed to pay a total of $2.5 million in penalties and has committed to implement projects at the Commerce City Refinery to improve electrical reliability at a minimum cost of $8 million, said Suncor spokesperson Leithan Slade in a statement to The Denver Gazette. “A plan for these projects is still being determined and will be submitted to the CDPHE. The work must be completed by December 31, 2026.”

Suncor said it is committed to improving performance and meeting regulatory requirements and said it achieved a 26% reduction in total hours of pollution exceedances in 2023 over 2022.

“This historic enforcement package, which includes both a penalty and required facility improvement projects, is the largest our agency has ever reached for a single facility for air pollution,” said Executive Director Jill Hunsaker Ryan, Colorado Department of Public Health and Environment, in the release. “Today’s actions demonstrate our unwavering commitment to environmental protection and the health of our residents. The agency will continue to use every tool available to prevent Suncor from having future violations.”

“Suncor is one of four Colorado facilities required to conduct fenceline monitoring under the state’s 2021 Air Toxics Act,” said the CDPHE release.

The fenceline monitoring settlement resulted from negotiations with CDPHE and voluntary actions by Suncor during a lawsuit filed by Suncor against CDPHE in September 2022 in Adams County District Court.

While the lawsuit was pending, Suncor voluntarily installed an interim fenceline monitoring system that was launched on January 1, 2023, and — according to Suncor — met the requirements of the state fenceline monitoring law.

“Data from our fenceline monitoring system indicates that measured covered air toxic compounds have remained below detection since the program began,” said Slade. “This system can be accessed in real time at https://suncor.data.spectrumenvsoln.com/. The final fenceline monitoring system will be operational by the end of this year.”

In October 2022, environmental law firm Earthjustice intervened in the lawsuit representing GreenLatinos, the Elyria-Swansea Neighborhood Association, Healthy Air and Water Colorado, Womxn from the Mountain, Conservation Colorado, and Sierra Club, alleging that CDPHE was not imposing strict enough requirements on Suncor.

In its lawsuit, Suncor alleged CDPHE exceeded its legal authority by, among other things, adding “a laundry list of compounds that are not even hazardous air pollutants” that had to be continuously monitored.

“The Division improperly disapproved and made significant modifications to Suncor’s fenceline monitoring plan that not only exceeded the Division’s legal authority, but that also prevented Suncor from being able to comply with the Fenceline Monitoring Law,” according to the lawsuit.

Suncor said CDPHE changed its mind and told the company to build the monitoring system Suncor had originally proposed — that CDPHE originally rejected — “only to require Suncor to tear it down and re-design, re-order, and re-build a completely new system six months later.”

Slade said Suncor has gone above and beyond CDPHE’s and the law’s requirements by voluntarily developing and launching a community air monitoring program for Commerce City and North Denver neighborhoods in 2021.

“Data gathered from that program, with monitors placed throughout the community, shows that levels have consistently remained below the acute and chronic health-protective guideline values routinely used by state and federal public health agencies,” Slade said.

About $1.3 million of the settlement “will fund projects to benefit disproportionately impacted communities through the state’s environmental justice grant program, and about 40% will go toward the state’s general fund. A small portion will go to the U.S. Environmental Protection Agency as required by a previous joint U.S. EPA/Colorado enforcement action,” said the CDPHE release.

“Colorado continues to hold air pollution sources accountable when they violate the law,” said the department’s Air Pollution Control Division Director Michael Ogletree in the release.