UPS Inc. has agreed to install air conditioning in package cars as part of language contained in the proposed master contract between the company and the Teamsters union, the Teamsters said Tuesday night.

New tentative contract language would mandate in-cab AC systems in all of UPS’ package cars purchased after Jan. 1, 2024, the Teamsters tweeted Tuesday night. Two fans would be installed in the cab of all package cars as well. All newer non-electric package cars and vans would be installed with exhaust heat shields to further protect drivers.

Also, all package cars would be retrofitted or equipped with air induction vents in the cargo compartments to alleviate extreme heat in the back of the vehicle, the Teamsters said.

“Air conditioning is coming to UPS,” tweeted General-President Sean O’Brien.

UPS has never had air conditioning in its package cars, arguing that frequent stops and starts would render such systems effectively useless.

UPS confirmed Tuesday night that it had reached an agreement with the Teamsters over heat safety that includes the use of new “cooling gear.”

The language must be ratified by the 340,000 UPS rank and file. The current five-year contract expires July 31, 2023.