MIDLAND, Mich. (AP) _ A worker at a Dow Chemical Co. plant died early today after being exposed to a raw material used in the production of herbicides, company officials said.

James Keeley, 29, was a head operator at Dow Chemical's AgroSciences phenoxy herbicide plant.

He went into cardiac arrest about 3 a.m. while being decontaminated after being exposed to 2, 4-dichlorophenol _ a chemical that can cause severe burns and affect internal organs if absorbed into the skin.

Co-workers took Keeley to a hospital, where he was pronounced dead.

Company officials were investigating and said they did not immediately know how Keeley was exposed.