Mosaic Co. Chief Executive Jim Prokopanko will take a medical leave of absence beginning June 1 for surgery to treat cancer.

Prokopanko, who is 60, announced in March that he had been diagnosed with cancer and was being treated with chemotherapy. He has continued to run Plymouth-based Mosaic, one of the world's largest fertilizer producers.

Starting June 1, Larry Stranghoener, Mosaic's chief financial officer, will become interim CEO until Prokopanko returns, according to a company filing Thursday with federal securities regulators.

Upon Prokopanko's return, Stranghoener will become Mosaic's executive vice president for strategy and business development until his planned retirement on Dec. 31. Richard Mack, Mosaic's general counsel, will become chief financial officer, the filing said.

Mike Hughlett