U.S. Sen. Cory Gardner and members of Congress from both chambers and both parties sent a letter to congressional leadership on Tuesday requesting a delay in a $15.5 billion tax on health insurance companies.

“That fee would be passed down to families, small businesses, seniors, Americans with disabilities, and state Medicaid programs,” the members wrote. “The price increases would particularly impact seniors and Americans with disabilities that utilize Medicare Advantage.”

The Health Insurance Tax, or HIT, was part of the 2010 Affordable Care Act. It levies a fee on health insurers derived from their premiums and market share. Congress put a moratorium on the HIT in 2017, allowed it to resume in 2018, and suspended it in 2019.

In January, Gardner and five other senators introduced the Health Insurance Tax Relief Act to provide a further two-year delay of the HIT.

The Centers for Medicare and Medicaid Services, in a review of health expenditures nationally in 2018, found that the 13% increase in the cost of health insurance was attributable “primarily to the reinstatement of the health insurance tax in 2018.”

While the HIT would be a cost passed on to consumers in the form of higher premiums, the revenue is part of the ACA’s mechanisms to subsidize coverage and reduce the deficit.