Asbestos Spill Shuts 405 Freeway : Hazardous materials: The northbound lanes remained closed through rush hour after the dust fell from a truck.

Commuter traffic was backed up for miles Friday after a bag containing asbestos fell off a flatbed truck and spilled onto the northbound San Diego Freeway, forcing its closure.

The spill occurred shortly after noon in Van Nuys, just north of the Sherman Way exit, and the freeway remained closed throughout the evening, causing a massive traffic jam. Cleanup crews began working with special equipment before 8 p.m., but the one-mile stretch of freeway was not expected to be reopened until after midnight.

The cleanup was conducted by a private contractor using high-powered water hoses and vacuums, as well as hand scrapers to remove dried asbestos from the grooves in the pavement.

The California Highway Patrol closed all four northbound lanes of the freeway after the 12:20 p.m. incident to prevent cars from stirring up the cancer-causing dust, which spilled from a 500-pound plastic bag containing an asbestos-sawdust mixture.

Only about 75 pounds to 80 pounds of the dust that was spilled was asbestos; the rest was sawdust, officials said. Hazardous-materials experts said the spill did not pose a serious health threat because the dust had been soaked with water before being transported and was lying on the freeway. Asbestos fibers can cause cancer if they become lodged in the lungs.

“Without traffic going over it and stirring it up, it’s no problem,” said Capt. Richard Hanson of the city’s hazardous materials unit.

Truck driver Melvin Rousch, 51, of Carson said that he was transporting the mixture from a building renovation in the 5700 block of Wilshire Boulevard to a dump in Stockton. Rousch said he was alerted by another truck driver on his CB radio that the asbestos bag was about to fall off the truck, but could not stop in time.

“As I was pulling over, I saw the dust in my mirror,” he said. “It already had fallen.”

CHP Officer Tim Liddell said that Rousch, a driver for J. Cal Transport, had permits for transporting asbestos and appeared to be following the appropriate procedures, but he said the CHP was still investigating the incident.

The asbestos-sawdust mixture had been watered down and placed in plastic bags. Each bag was in a cardboard box and the truck was carrying 26 such boxes, Liddell said.

A heavy plastic bag broke through the box, and split open when it hit the highway.

Traffic was routed off the freeway at Sherman Way and allowed back on the highway on the Roscoe on-ramp, Officer Vince Zambrana said.

Traffic on the northbound lanes was backed up for several miles, officers said, and traffic on the southbound lanes also slowed to a crawl. Meantime, surface streets near the freeway became clogged as motorists sought alternate routes.

Several cars on the freeway overheated and further slowed movement. One motorist caught in the massive traffic jam had to be treated by paramedics after he flagged down a CHP officer and complained of heart problems.

Surveying the sea of slow-moving cars on the freeway, Caltrans Supt. Bruce W. Dyar said: “It’s Friday the 13th. Goblins must be in the air.”

OTHER TRAFFIC JAMS:A1