Flames from the gas explosion in Des Moines

DES MOINES, Iowa (CNN) -- Thousands of evacuees are back in their homes after firefighters put out a potentially calamitous fire blaze at a liquid propane plant northwest of Des Moines. There were no injuries from Wednesday's fire, which began shortly after 5 p.m. and was extinguished more than five hours later.

Authorities said the emergency began when a 2,800-gallon tanker truck caught fire at the Cenex Propane plant as it pulled away from a 30,000-gallon filling tank. Another tanker truck and a flatbed truck filled with small tanks also went up in flames.

One of the tanker fires had burned itself out by late Wednesday and crews managed to extinguish the flames on the other two trucks and hit a shutoff valve on the filling tank, ending the leak.

The emergency came amid frigid temperatures and about 7 inches of new-fallen snow. A voluntary evacuation was in effect for homes and businesses within about a mile and a half from the site, an area with at least 10,000 people and three hotels, officials said.

A nearby section of Interstate 80 also was closed for a time.

Fire officials said there could have been a massive explosion if flames had reached storage tanks at the plant containing 1.5 million gallons of liquid propane.