Two explosions ripped through a chemical plant in Pampa, Tex., killing three people, injuring 37 and touching off massive fires, authorities said. One worker was missing. At least 25% of the Hoechst Celanese Chemical Co. plant burned so hotly that firefighters could not get closer than a half-mile from the plant and decided to let it burn itself out, Mayor David McDaniel said. At least 60 nearby residents were ordered evacuated and people were kept away from their homes because of the possibility of a third explosion, McDaniel said. The fires apparently stemmed from a butane explosion that flattened the plant's control room. McDaniel said the fumes, laced with acetic acid, were not considered dangerous. The blasts shook the 775-acre plant when a weekend crew of about 40 people was working, police said. After seeing a boiler explode, workers began running, and "we made it about two feet out of the control room, and the (building) just disintegrated," said worker Ted Rodgers, who was treated for minor injuries.