Traffic was jammed for hours yesterday after scrap metal loaded in a large open truck scraped the underside of a Bellmawr overpass, punctured an overhead water main, and scattered across a major road during morning rush hour.

The accident, at about 8:15 a.m., left water gushing from the broken pipe and large pieces of metal across most lanes of westbound I-76.

No one was injured in the incident, which caused damage to six cars that hit debris, according to New Jersey State Trooper Rod Jones of the Bellmawr barracks.

Authorities said that minor damage to the overpass will not affect traffic today, and that the water main will likely be repaired during off-peak hours.

The truck was owned by Longhorn Transport of Newark, N.J., which Jones said is expected to be held responsible for costs resulting from the accident. Police did not identify the driver. A spokesman for Longhorn could not be reached for comment yesterday.

The truck was attempting to travel under the Browning Road overpass on I-76, near where traffic enters from northbound Route 42 and I-295. The wide artery connects Route 42 and I-295 to the Walt Whitman Bridge.

All three roads and northbound Route 55 immediately became gridlocked. By 10 a.m., traffic was backed up seven miles on northbound Route 42, all the way to the Atlantic City Expressway, according to New Jersey State Trooper Phil Campbell of the Bellmawr barracks. Route 55 also was jammed for seven miles.

Ronald Austin, a cook at the Abigail House Nursing and Rehabilitation Center in Camden, was driving up Route 42 from Williamstown with his children when they came upon the accident, which had just occurred.

"Traffic was running really well, then it just came to a complete stop," he said.

It took an hour to get from the Deptford Mall exit to I-295, Austin said - a distance he usually covers in minutes.

"My kids were an hour late to school," he said. "I was an hour and a half late to work."

The driver of the truck was on his way from Newark to Camden when the mishap occurred. The impact with the overpass tore the door off the back of the truck and released the cargo onto the road, Jones said.

Troopers are not yet certain whether the metal was piled too high in the open truck bed or if the trailer itself was too high, Jones said.

The driver told police that the trailer stands 131/2 feet tall, which should have allowed it to pass under the overpass, which Jones said has a height of 13 feet, 11 inches.

The roadway was fully cleared by 12:30 p.m., according to Trooper Robert Montgomery of the Belmawr barracks.