One day after The New York Times reported that more than 2,100 ventilators from the government’s national stockpile were inoperative due to a lapsed federal contract, U.S. Sen. Cory Gardner demanded an investigation into the maintenance history of the devices.

“How long did the ventilators go without maintenance compared to industry standards?” Gardner wrote in a letter to the U.S. Department of Health and Human Services’ inspector general. “Was there mismanagement that led to a shortage of working ventilators or other critical medical supplies or equipment?”

According to The Times, state officials reported to the federal government that ventilators they had received from the stockpile of medical equipment were nonfunctional. Due to a delay in awarding a contract, there was no one responsible for maintaining the ventilators between the summer of 2019 and January 2020. It was unclear whether the problems in the equipment existed before last summer.

“These reports, if true, are unacceptable and I am writing to urge the immediate investigation,” wrote Gardner.

Ventilators help a patient to breathe through the insertion of a tube. One study of COVID-19 patients in China found that nearly half of those in intensive care required invasive ventilation to treat the virus. In a letter to the White House on March 28, Gov. Jared Polis requested 10,000 ventilators for Colorado.