Roughly 500 GE Healthcare workers in Wisconsin could go on strike on Aug. 12 unless progress is made in the next round of contract negotiations between the International Association of Machinists and Aerospace Workers and the company.

The IAM rejected GE's contract offer Tuesday and gave the company its 10-day notice of a potential strike by its members.

GE and the unions are scheduled to go back to the bargaining table Sunday and a strike could be postponed or averted.

The contract negotiations affect workers in Waukesha, Milwaukee and Oak Creek.

The contract negotiations also include the International Union of Electronic, Electrical, Salaried, Machine and Furniture Workers - Communications Workers of America, or IUA-CWA, which represents few if any any of GE Healthcare’s workers in Wisconsin.

The two unions represent workers in Wisconsin and Ohio at GE’s healthcare and aviation units. Both are GE’s more profitable businesses.

“We continue to believe that the proposed four-year contract provides solid wage increases and improved benefits to employees while keeping our businesses competitive,” GE said in a statement. “The agreement has been endorsed by the leadership of our largest union, the IUE-CWA, and ratified by several Coordinated Bargaining Committee (CBC) unions covering nearly 1,100 members.”

The IAM said its concerns include wages, overtime, health care and retiree benefits.

“It’s time for GE to recognize the value our members contribute to the economic health of this corporation and bargain a fair contract,” Brian Bryant, IAM general vice president, said in a news release.

GE said the average wage for the unions’ members is $31 an hour, or $64,480 a year.

The company has proposed general wage increases totaling $1.80 an hour, or $3,744 a year, a ratification bonus of $1,500 and cash payments in 2021 and 2022 totaling $3,000.

But it also has proposed increases in workers’ contributions to the cost of their health benefits in 2021 and 2020.

A worker's share of the cost for family coverage would increase in three of the four years of the contract, going up by $849.16, to $5,372 a year, for family coverage in the fourth year. The annual deductible also would increase to $250 a year, according to the company.