The Colorado Department of Public Health and Environment’s Air Pollution Control Division held a pair of public meetings last March on the initial monitoring plan, which Suncor submitted to the state in December 2021. Ogletree said community feedback helped the division decide whether to force the company to report on 11 additional airborne toxins in addition to the three chemicals required under the original legislation.

The division will require further changes focused on specific air monitoring equipment, Ogletree said. Suncor officials originally proposed using swiveling air monitors that rotate to sample pollution from different wind directions.

State regulators were concerned the system could miss emissions based on the orientation of the sensors and determined the plan did not meet a legal requirement for “continuous” air monitoring, Ogletree said. Instead, the state will require the company to install fixed monitors and double the number of sensors.

In the event of a spike in air pollution near the refinery, Suncor must alert its neighbors by email and text message. The division plans to set lower thresholds for sending these emergency notifications than was originally proposed by Suncor. Additionally, anyone worried about even smaller pollution spikes — small enough to fall below EPA thresholds for hazardous exposures — can sign up for additional notifications.

Renee Millard-Chacon, an environmental justice organizer who lives less than two miles from the Commerce City refinery, said she was pleasantly surprised by the state-mandated changes.

“Honestly, this all sounds great. It’s a long overdue step in the right direction, but the question now is how will this lead to enforceable regulations with real teeth?”

The state-mandated fence system will be added to the top of a network Suncor voluntarily built last summer that includes 10 air monitors within three miles of the refinery. Cultivando, a health and environmental nonprofit in Commerce City, operates an independent monitoring station and mobile data collection van.

Suncor spokeswoman Amy Fidelis said the company supports air monitoring but would not comment on the specific changes required by regulators.

“The refinery has received feedback from the Colorado Department of Health and Environment on its fence monitoring plan and is in the process of reviewing it,” Fidelis said.