The Chicago Zoological Society, which operates Brookfield Zoo, and the Teamsters Union averted a possible strike of nearly 220 zoo workers after reaching a tentative deal on a new five-year contract last week.

Teamsters Local 727 represents both full-time and seasonal employees at Brookfield Zoo, including zookeepers and groundskeepers to police officers. The two sides succeeded in hammering out a tentative deal on April 21 after failing to reach an agreement during a negotiating session on April 18.

“We are very pleased that we were able to reach an agreement and hope the union members will vote in favor of the new contract,” said Sandi Dornhecker, vice president of human resources for the Chicago Zoological Society, in a press release. 

On April 14, the union had announced that the Chicago Zoological Society had pushed workers to “the brink” of a strike by insisting that the employees shoulder the entire burden of health care cost increases.

“These workers do not want to go on strike, but if management continues to mistreat them and make unreasonable demands, they will be forced to stand up for themselves,” said John Coli Jr., president of Teamsters Local 727 at that time.

According to the union, the Chicago Zoological Society had insisted that workers bear the cost of $6.5 million in health care increases over the term of what at the time was a proposed four-year contract.

“Forcing our members to shoulder such costs would be devastating to the workers and their families,” Coli said in an April 14 press release.

Coli also announced at that time that the union had filed an unfair labor practice complaint against Chicago Zoological Society management “stemming from the company’s complete misrepresentation of the ongoing contract negotiations in an April 5 email to bargaining unit members.”

It’s unclear who will bear the health care cost increases in the tentative deal. The Chicago Zoological Society, in the press release issued April 21, would say only that “both sides made significant movement in their positions and worked hard in an effort to reach middle ground.”

The union indicated on April 21 that the new contract “preserves health care benefits” for workers, but does not indicate whether employees will pick up a greater portion of those costs. 

The previous four-year contract expired on Dec. 31, 2015, but both sides agreed to extend the deal while negotiations, which began last November, continued.