A Florida-based oxygen tank provider will reimburse Washington state’s Medicaid program after investigators found it had fraudulently overbilled patients for leased oxygen equipment.

Officials with the Washington Attorney General’s office say Lincare knowingly billed rental fees for oxygen equipment in excess of what is permitted by law more than 15,000 times. Those officials estimate that 565 Medicaid patients in Washington state were overbilled by more than $500,000.

Medicaid provides oxygen equipment on a five-year contract. Under Washington state law, Medicaid pays rental fees on oxygen equipment for three years. For an additional two years, providers like Lincare can continue to bill for maintenance and supplies but may no longer charge rental fees. After that, the device is eligible for replacement. Investigators say Lincare was charging rental fees beyond that three-year limit, up to six years in some cases.

In addition to reimbursing the state’s Medicaid program, Lincare will comply with Washington’s oxygen leasing laws and also will ensure it has internal controls to prevent further violations.

This isn’t the first time Lincare was found to have been accused of illegal billing practices. In August 2023, Lincare entered into a $29 million resolution with the U.S. Attorney for the Eastern District of Washington. That resolution required the company to make significant billing reforms and practices and retain, at its expense, independent experts to review its claims and billing practices to ensure they are lawful.

Lincare has a supply facility in Kennewick.