A massive steel tank broke loose from a tractor-trailer Monday morning and tumbled onto Route 72 near Manheim, demolishing two cars and injuring two motorists.

The accident seriously injured a Manheim teenager, whose car was struck head-on by the tank, according to state police. A 36-year-old Manheim woman also was hospitalized after the tank hit her Volvo, police said.

The 38,000-pound tank, which was empty, was being hauled on a flat-bed trailer about 7:30 a.m. when a chain holding it in place snapped and it rolled onto the road, police and fire officials said.

The tank broke loose as the truck driver, Charles Smith Jr. of Manheim, negotiated a right turn just south of Pinch Road in Rapho Township. The rig was traveling north on Route 72; the two cars were headed south.

The rolling tank first struck the driver's side of Melanie Thompson's Volvo, forcing her car off the road and into an embankment. Thompson was taken to Lancaster General Hospital. Her injuries are not life-threatening, investigators said.

Shawn Custer, 17, was driving behind Thompson when the tank smashed into his Pontiac, police said. Trooper Robert Maher said Custer sustained "serious injuries" and was being treated at Lancaster General Hospital.

The tank came to rest in front of 2250 Lebanon Road (Route 72). Both cars were demolished.

The 59-year-old truck driver was not hurt. No charges were filed against him Monday, police said.

Capt. Jeff Siegrest of the Mastersonville Fire Company was one of several officials who helped with the cleanup. He said the tank, which looked similar to a propane tank, was lifted by a crane back onto the flatbed trailer.

Both lanes of Route 72 were closed for more than four hours, officials said.

Manheim firefighters assisted Mastersonville's fire crew at the scene. Ambulances from Brickerville and Manheim transported the victims to LGH.

E-mail: bhambright@lnpnews.com