Negotiators with the United Steelworkers have reached a tentative agreement on a new contract for 950 workers at the Bridgestone-Firestone factory in Des Moines.

Bridgestone-Firestone makes tires for tractors and farm implements. The current contract for 4000 workers at the company’s factories in Iowa and four other states expired at 11 last night. Employees are still at work and union members will vote on the new contract proposal soon.

A statement posted on the United Steelworkers’ Facebook page doesn’t share details, but said there are “solid breakthroughs and significant gains: in the contract offer.