FIELD LAB'S BIG CONCERN IS MUDSLIDES.

Byline: Kerry Cavanaugh Staff Writer

Mudslides and erosion are the biggest risks from the Santa Susana Field Lab after last month's Topanga Fire, which scorched 2,000 of the 2,800 acres at the hilltop facility, Boeing officials said Thursday.

Neighbors and lab watchdogs had expressed concern that the fire may have spread contamination off site in smoke or ash, but Boeing and a number of environmental regulators have said they don't believe that occurred.

``It's not contamination, it's mud we're concerned about,'' said Paul Costa, Boeing's manager of environmental protection at the lab.

During the blaze, some firefighters worried that they may have been exposed to contamination and that prompted the Ventura County Fire and Environmental Health Services departments to investigate risks on the property. The agencies decided the burning brush at the lab didn't pose a threat.

``I think there are other things up there that could pose a risk to firefighters, but we were lucky,'' Fire Department Hazardous Materials Officer Steve Baker said. ``Some of the areas that might be a concern were spared from the fire.'' On a tour of the rocket testing and former nuclear research facility Thursday, officials pointed out hazardous and radioactive material storage buildings that came through the fire unscathed. Ten other buildings, all vacant or no longer in use, were destroyed.

Soil, trees and vegetation burned throughout the lab area, and workers have laid down new plastic tarps over contaminated sections to prevent rain from washing tainted soil off site.

Boeing officials do expect to see higher levels of certain contaminants in runoff from the site of the fire but said there's a larger risk of slides. The storm earlier this week dropped about an inch of rain on the lab but caused little damage.

``If we had another couple more inches, we could have had problems,'' Costa said.

Lab officials are spreading hay, rock and plastic tarps to prevent mud movement.

Some lab watchdogs were disappointed that no agency tested the air for chemical or radioactive elements during the fire.

``No agencies were able to answer what kinds of airborne contaminants may have been produced. The lingering questions were what measurements were made,'' said Dan Hirsch with the Committee to Bridge the Gap.

Boeing tested the air for radioactive materials during part of the fire and sampled ash after the blaze but picked up no contaminants.

The South Coast Air Quality Management District conducted one-time tests for chemicals in the air in Chatsworth, Porter Ranch and West Hills several hours after the field lab burned. They compared the results to recent samples taken in Sun Valley, said Rudy Eden, with the district.

``There was nothing we consider unusual at all in these results.''

Kerry Cavanaugh, [phone]

kerry.cavanaugh(at)dailynews.com