The U.S. refining hub of Texas has accounted for at least seven of the 12 separate fire incidents in refineries across the country so far this year.

This included a blaze that killed one worker and injured two others at Marathon Petroleum's Galveston Bay refinery, one of the largest in the U.S. in terms of capacity, on May 15, prompting investigations by federal and state agencies. Just two days later, another fire broke out at Valero's Corpus Christi plant.

Over 47% of total U.S. petroleum refining capacity is located along the Gulf coast, according to the U.S. Energy Information Administration.