COMMERCE CITY, Colo. (KDVR) — Higher-than-normal levels of air pollution were found in the areas surrounding the Suncor refinery, the Colorado Department of Public Health and Environment said.

CDPHE reported high levels of sulfur dioxide were found in Commerce City Wednesday morning. However, the department confirmed that although the levels were higher-than-normal they did not exceed federal standards.

According to the National Ambient Air Quality Standards, air pollution standards are measured in one-hour increments and it is 75 parts per billion per hour. Air monitors near Suncor recorded two short-term spikes, one that measured 115 parts per billion and another at 186 parts per billion.

CDPHE said the numbers dropped significantly at 9 a.m. Wednesday and slowed to normal levels again.

Why was there a spike in air pollution?

According to the refinery, a sulfur recovery unit associated with a tail gas unit was briefly offline and that caused an excess of sulfur dioxide, a flaring of acid gas and elevated hydrogen sulfide in the fuel gas system.

The units went offline due to a level indicator issue.

Impacts of exposure to sulfur dioxide

CDPHE sent a warning that even short-term exposure to sulfur dioxide can exacerbate asthma and make breathing difficult.

When potentially unhealthy levels of sulfur dioxide are in the air, CDPHE said people should:

  • Limit strenuous activity outside
  • Keep windows and doors closed
  • Use an air conditioner and set it to recirculate
  • Consider using an indoor air purifier

Previous Suncor closure

In December 2022, the Suncor refinery was closed for months after two employees were hurt in a fire.

“It was determined that the entire facility would be shut down and put into safe mode to allow for the inspection of all units and repair of the damaged equipment,” Suncor’s statement said in part.

In early March, Suncor prepared to restart full operations again.