Colorado Attorney General Phil Weiser is looking into complaints from people across the state that AmeriGas hasn’t been delivering their propane for weeks, leaving them at “emergency levels” this winter.

Weiser said Wednesday that he sent a letter to AmeriGas asking to meet with the company’s attorneys. Customers’ repeated calls for service have gone unanswered, Weiser said in a statement.

“Many Coloradans rely on propane as their primary source of fuel for heating their homes. Reliable access to propane is essential, especially during this winter when we have had record cold temperatures in the state,” said Weiser.

But Colorado customers have said that AmeriGas, which operates nationwide, has been unable or unwilling to service their tanks, Weiser said.

AmeriGas said in an email that it has received Weiser’s letter and is investigating the claims.

“At times, it appears that AmeriGas charges consumers extra fees for emergency deliveries—emergencies that AmeriGas itself created,” Weiser wrote in the letter to Paul Ladner, president of the Pennsylvania-based company.

The lack of service is endangering Coloradans and might violate the Consumer Protection Act, Weiser said. The company has until March 1 to respond and say what measures it will take to protect Colorado consumers, he added.

Weiser said people having similar problems can file a report with his office.

“To date we have not received a specific customer complaint directly from the Attorney General’s office of Colorado. We closely monitor demand and proactively allocate resources where needed, but like other industries, we are still facing driver shortages,” AmeriGas said in an email.

The company said it continues to recruit and hire drivers throughout Colorado. “AmeriGas is proud to be a long-time propane provider in Colorado and looks forward to safely providing customers with the service they expect and deserve for many more years to come.”

The company has 1.28 million customers across all 50 states.