COLUMBUS, Wis. (AP) -- A man working on a 321-mile oil pipeline project was killed after a piece of machinery overturned on him in southern Wisconsin.

The Columbia County sheriff's office says 39-year-old James Green, of Michigan, was crushed and he was pronounced dead about a quarter mile north of Highway K yesterday.

Green was using the trackhoe to move a concrete weight that is used to stabilize pipeline in wetland areas. It wasn't immediately clear what caused the trackhoe to tip over.

Houston-based Enbridge Energy is building the pipeline. Company spokeswoman Denise Hamsher says work at the site had stopped until Occupational Safety and Health Administration officials could investigate. They were expected on the site tomorrow.

Green had been working on the pipeline for about a year.

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