GM said in a statement that its offer to the UAW during talks included more than $7 billion in new investments, 5,400 jobs - a majority of which would be new - pay increases, improved benefits and a contract ratification bonus of $8,000.
The UAW represents almost 150,000 employees at GM, Ford and Fiat Chrysler.
A broad strike by the union would be the first such action at GM in 12 years and would test both the union and GM Chief Executive Mary Barra at a time when the USA auto industry is facing a slowdown in sales, and rising costs for launching electric vehicles and curbing emissions.
The UAW said the Aramark workers have been in negotiations since March 2018, and the company and union are at odds over pay and benefits.
But, Tiller said, union members are frustrated by practices, such as GM hiring temporary contractors instead of permanent employees.
The United Auto Workers (UAW) turned up the pressure on General Motors Co, threatening a strike by Sunday night if the company does not agree to its terms and ordering 850 maintenance workers at five GM facilities to walk off the job.
A source close to the UAW with direct knowledge of negotiations said most of the proposals the company disclosed publicly on Sunday came very late in negotiations Saturday.
Before talks collapsed, GM offered UAW workers "improved" wages and healthcare benefits as well as $7 billion in USA investments and the addition of 5,400 jobs. Of those employees, 947 are hourly workers and 154 are salaried.
"It's not something taken lightly".
GM has factories in Michigan, Ohio, New York, Kentucky, Tennessee, Texas, Missouri, Indiana and Kansas.
While the details of the product are still a secret, an individual familiar with the matter told CNN that GM's offer specifically pointed to the allocation of an upcoming electric truck to Detroit-Hamtramck and its battery production to Lordstown.
The union had earlier extended the contracts at two other United States automakers with UAW contracts, Ford and Fiat Chrysler, as it targeted GM in an effort to reach a deal that would set a pattern for the industry.
GM announced last November it was effectively shuttering five plants in North America, including facilities in MI and OH that were "unallocated" for production. That's well above the industry average of 61. "These are profitable times. and we deserve a fair contract". It took place after a private meeting between the UAW and GM. That is about the time we saw union members start to picket around the General Motors plant in Wentzville. "We knew this would be the year we had to make a stand", said Elzy, who called in Sunday night to confirm his picket assignment and reported for duty before daylight Monday.