Three workers died and at least 37 were injured January 29 in a thunderous blast that blew the roof and doors of a Kinston, N.C., pharmaceutical plant 400 feet in the air and created a toxic plume of black smoke visible for miles.

Hundreds of firefighters and emergency medical workers rushed to the 28-year-old West Pharmaceutical Services factory, where officials estimated 134 people were on duty when the explosion occurred.