An explosion at the Nestlé Purina plant in Flagstaff, Arizona, has injured four workers.

The plant, which employs about 250 workers and produces 1,000 tons of dry dog and cat food a day, experienced a grain-dust explosion Sunday evening.

Four contractors were doing welding work on the fifth floor of the plant, which is about 5 miles northeast of downtown Flagstaff, when dust produced during the food-making process ignited, according to Flagstaff Fire Department Capt. Bill Morse. Continue reading →