(FOX 2) - Thousands more autoworker union members have joined the UAW's strike Monday after employees at Mack Trucks rejected a tentative agreement with their parent company.
According to a letter from UAW President Shawn Fain, 73% of workers that build trucks at plants in Maryland, Pennsylvania, and Florida voted down the latest contract offer. As of 7 a.m., 4,000 employees went on strike.
They join the tens of thousands of other UAW members who are already picketing the Detroit 3 after negotiations with General Motors, Ford, and Stellantis failed to reach a deal in September.
"As you are aware, UAW members and workers across the economy are mobilizing to demand their fair share," read Fain's letter Volvo Trucks, which owns Mack Trucks. "Over the last three months, we have met with Company representatives in an effort to address issues raised by our members.
"The Union remains committed to exploring all options for reaching an agreement, but clearly we are not there yet."
The letter cited wage increases, cost-of-living allowances, holiday schedules, and retirement security among the issues at play.
A tentative agreement was reached on Oct. 1.
UAW Locals 171, 677, 1247, 2301, and 2420 in UAW Region 8 and Region 9 represent workers at Mack Trucks in Macungie and Middletown, Pennsylvania; Hagerstown and Baltimore, Maryland; and Jacksonville, Florida.
The deal negotiators had reached with Mack just over a week ago included a 19% pay raise over the life of the contract with 10% upon ratification. There also was a $3,500 ratification bonus, no increase in weekly health care contributions, increased annual lump sum payments for retirees and a $1,000 annual 401(k) lump sum to offset health care costs for employees who don’t get health insurance after retirement.
Mack Trucks President Stephen Roy said in a statement Sunday night that the company is "surprised and disappointed" that the union chose to strike. The union, he wrote, called the tentative agreement a record for the heavy truck industry. "We trust that other stakeholders also appreciate that our market, business and competitive set are very different from those of the passenger car makers," the statement said.
Mack, he wrote, is part of the only heavy truck manufacturing group that assembles all of its vehicles and engines for North America in the U.S., competing against trucks built in lower-cost countries.
The Associated Press contributed to this report