ELYRIA, Ohio (AP) _ An explosion today at a farm building where welding flux was manufactured burned at least four people, two critically, authorities said.

Kenneth Chutes, 23, and Harry Greenwood, 24, both of Lorain, had first- and second-degree burns ''over a good portion of their bodies,'' and were being transported to Cleveland's Metro General Hospital, Elyria hospital spokesman Robert Olesen said.

He said two other people were being treated and would probably be released. He added that the hospital may get one or two more injured people from the scene in Eaton Township.

The explosion was reported at about 8:30 a.m., said Eaton Township fire dispatcher Georgianna Spriestersbach. She said the site was about one-half mile north of the intersection of Ohio routes 82 and 83 southeast of Elyria.

The manufacturer was Rossborough Mfg. Co., based in Avon Lake, a person who answered the phone at Rossborough confirmed. She would not give further details about the operation until company officials, who were at the scene, could be reached. Flux is an agent used to help metal fuse by preventing oxidation.

There were no reports of any fatalities, and a sheriff's dispatcher said at least three people were injured.