KINSTON, N.C. (Jan. 31)—An explosion at a West Pharmaceutical Services Inc. facility that killed three people and injured 37 may have been caused by an ignitable cloud of rubber dust, investigators said Thursday after interviewing employees, according to Associated Press reports. The Jan. 30 explosion destroyed a large portion of West's manufacturing facility where the company compounds and mixes rubber that is distributed to other West plants, and where it also makes intravenous fitments used for drug delivery systems. The process of making rubber produces significant quantities of dust, according to a statement from the U.S. Chemical Safety and Hazard Investigation Board. "Investigators are pursuing a theory that the massive explosion which led to the destruction of the plant was caused by ignitable dust cloud," the board said. The board, which will start testing dust and other plant samples, estimated damage to the building at $150 million.