Two workers were killed and nine others injured in an explosion Wednesday at a oil field in west Texas, local media reported. The blast was caused by a buildup of pressure while workers were changing a wellhead, said the reports, citing local police. The two workers, whose names have yet to be released, died at the scene while the nine others incurred minor injuries. No more details were available, police said, as radio communications and cellphones don't work well in the rural area.