By Thomas Watkins
The Associated Press

AP Photo/Rick Francis Los Angeles County firefighter Darrick Woolever examines metal that needs to be removed Monday, at the Universal Studios Hollywood back lot, a day after a fire destroyed the New York Street facade.

UNIVERSAL CITY, Calif. — A massive blaze that destroyed part of the back lot at Universal Studios was accidentally ignited by workers using a blowtorch on the roof of a movie set building facade, fire officials said.

Workers had been using the blowtorch early Sunday to heat asphalt shingles to apply to the roof, Los Angeles County Fire Chief Michael Freeman said Monday. They finished around 3 a.m. and followed policy of standing watch for one hour, then left for a break, he said.

A security guard spotted the fire and reported it at 4:43 a.m., Freeman said.

The fire erupted on a streetscape featuring New York brownstone facades at the 400-acre property. It then destroyed a King Kong attraction, the courthouse square from "Back to the Future" and a streetscape featured in "Spider-Man 2" and "Transformers."

The theme park reopened Monday, giving tourists a view of the fake streetscape that went up in real flames, and authorities promised to investigate reports that firefighters were hindered by low water pressure.

Freeman suggested the problem may have been due to the volume of water — 18,000 gallons a minute at the peak — that was poured on the flames. He said the studio's water systems were up to current county code.

The low water pressure forced firefighters to tap lakes and ponds at Universal, which is a working studio as well as a theme park straddling a pass through the hills between Hollywood and the San Fernando Valley.

It lies in county territory and operates and maintains its own water system, which is fed by the Los Angeles Department of Water and Power. But the city's involvement stops at Universal's property line.

"We had adequate water supply feeding their system and were in fact asked by the Fire Department to attempt to increase water pressure and we did so," DWP spokesman Joe Ramallo said.

The blaze burned for more than 12 hours but was contained to the back lot. It gutted a building housing 40,000 to 50,000 videos, but Universal Studios President and Chief Operating Officer Ron Meyer said there were duplicates of everything.

Nine firefighters and a sheriff's deputy suffered minor injuries. None of the 30 sound stages on the lot was damaged, and the New York streetscape will be rebuilt, studio spokeswoman Cindy Gardner said.

That meant the fire was "not disastrous for the overall industry," said Jack Kyser, chief economist at the Los Angeles Economic Development Corp. Sound stages are in high demand by producers and are expensive to build, he said.

Use of the New York streetscape was often at full capacity, though it was not in use when the fire broke out, Gardner said.

The smell of smoke hung in the air Monday as tourists on the park's tram ride applauded firefighters as they drove past. At least a dozen fire trucks remained on the lot as smoke continued to rise from thick, twisted piles of girders.

"We were a bit shocked," said Danish tourist Morten Jull, 20. "We were like, can this be?"

Another fire at Universal Studios in November 1990 caused $25 million in damage and was started by a security guard who was sentenced to four years in prison after pleading guilty to arson. After that fire, the New York streetscape was rebuilt in three months.