About two-dozen union workers at a Swissport cargo terminal at Denver International Airport went on a one-day strike Monday over what they say are unsafe working conditions.

The walkout was also do to complaints about wage and benefits and started Sunday night, according to a news release.

Service Employees International Union Local 105 officials said in the release that issues with “dangerous working temperatures” and “broken equipment” along with inadequate safety training have gone unresolved by the company.

The release said a loading truck struck an unprotected floor heater, causing a fire in the warehouse earlier this year.

Similar incidents at New York’s LaGuardia and Chicago’s O’Hare airports have “been raising alarms on the unsafe working conditions at Swissport facilities,” union officials alleged.

Attempts to contact SEIU representatives were unsuccessful.

Representatives of DIA said the protest ended just before noon on the Plaza, near the Westin Hotel, and there was no violence or any disruption of airport operations.

In a statement to The Denver Gazette, Swissport said most of their employees did not participate in the strike.

“Most of our employees fulfilled their scheduled hours and did not participate in the work stoppage,” according to a spokesperson in a statement. “Swissport continues to proactively address any issues or concerns raised by our team, reinforcing our enduring commitment to cultivating a positive and supportive work environment.”

The union’s release also said workers want “living wages” and benefits.

The company serves 92 airports in the U.S. and 294 airports worldwide. Services include passenger services, ramp handling of aircraft and baggage and air cargo handling, according to the company’s website.