Two of the city's largest school bus companies reached a tentative agreement with a union representing 900 of their bus drivers and attendants late Monday night, averting a strike that would have gone into effect this morning.

Mayor de Blasio's office broke the news on Monday.

The deal, which still has to go before union members for a vote, includes the provision that Jofaz Transportation and Y&M Transit will continue to provide health insurance at no cost to employees. One of the major grievances raised during last week's strike vote was what workers deemed an unfair percentage of their hourly wages being put towards healthcare costs.

"These are the workers that we entrust with the safety of our children, but starting wages for school bus attendants aren't much higher than minimum wage," said Demos Demopoulos, Secretary-Treasurer of Teamsters Local 553. "To increase the healthcare costs for these workers, many of whom are single mothers, is patently unfair."

Workers had also criticized a proposal to cut five of their paid holidays. Teamsters Local 553 couldn't immediately confirm if the holidays may still be chopped.

The drivers cover 600 elementary school and special education bus routes in Queens, Brooklyn and Staten Island, according to the Teamsters. The strike could have impacted more than 10,000 students, though the city had a contingency plan in the works involving city-subsidized MetroCards and reimbursement for parents for the cost of car travel or car fare.

"We are grateful to families and educators for their patience and support as we prepared contingency plans to provide transportation alternatives for students and families,” said Department of Education spokeswoman Devora Kaye in a statement.