Authorities are trying to figure out how six injured men were exposed to battery acid at an oil and gas drilling rig in New Martinsville.

Three of the men remained hospitalized Thursday, a day after being splashed with liquid and aerosol forms of battery acid at Chesapeake Energy's Procko Well 20 miles east of New Martinsville.

Wetzel County Hospital Chief Executive Officer George Couch said the men suffered skin irritations and respiratory problems.

Chesapeake Energy said in a prepared statement that the site has been secured and the public is not in danger. It said crews were working Thursday to remove equipment from the well.

The state Department of Environmental Protection and the Occupational Safety and Health Administration are investigating.