CHEYENNE, Wyo. (AP) — Wyoming workplace safety regulators are seeking $13,500 in fines against a Glenrock company for an oil facility explosion that killed three workers northeast of Casper.

The Wyoming Workers' Safety and Compensation Division released the citations Thursday. They allege seven violations by Wild West Construction in Glenrock, including that the company failed to adequately instruct employees how to recognize and avoid unsafe conditions.

The explosion happened Aug. 29. The citations say flammable substances flowed from an oil storage tank through a pipe to where the workers were welding.

Wild West Construction had no listed phone number and could not be reached for comment.

Tulsa, Okla.-based Samson Resources and Double D Welding and Fabrication in Mills also have received safety citations for the explosion. Proposed fines against all three companies exceed $48,000.