Around 480 business groups have teamed up to call on lawmakers to provide liability protections for businesses against coronavirus-related lawsuits in Congress’s next relief package.

The coalition, led by the U.S. Chamber of Commerce, includes the National Association of Manufacturers, Airlines for America, National Restaurant Association, Federation of American Hospitals and the National Retail Federation. They sent a letter to congressional leadership on Wednesday to keep pressure on Congress.

A liability shield for businesses, schools and other organizations was included in the GOP’s coronavirus package unveiled Monday. The issue is one of the biggest obstacles during negotiations to getting a deal on legislation.

“These crucial protections would safeguard healthcare workers, providers, and facilities, as well as businesses, non-profit organizations, and educational institutions against unfair lawsuits so they can continue to contribute to a safe and effective economic recovery from the COVID-19 pandemic,” the groups wrote.

The letter stresses that these business groups are pushing for timely, targeted and temporary liability relief provisions. The chamber and other business groups first made a strong call for liability protection in May.

“[O]ur members and constituencies remain concerned that, despite doing their best to follow applicable government guidelines, they will be forced to defend against an onslaught of frivolous lawsuits. Unfortunately, this concern has already begun to materialize,” the groups wrote.

Democratic leaders have indicated that a liability shield is a dealbreaker in negotiations while Senate Majority Leader Mitch McConnell (R-Ky.) said this week he will not bring legislation to the Senate floor unless it includes these protections.

The letter was also signed by the National Small Business Association, the Real Estate Roundtable, American Hotel & Lodging Association, Airports Council International – North America, National Association of Broadcasters, American Property Casualty Insurance Association, American Farm Bureau Federation, American Gas Association, and American Gaming Association, among others.