NEW YORK, Sept. 12 -- A member of the architectural firm that designed the World Trade Center says while asbestos removal programs were conducted in the towers that collapsed from Tuesday's attacks, it is possible some small areas remain, leaving open a potential health threat during rescue and cleanup operations.
At the time the two towers were constructed, from 1968 through 1972, the health threat from inhaled asbestos fiber was just beginning to be recognized. Until then, it was routine for the steel girders of skyscrapers to be sprayed with an asbestos material. After the health threat was known, other materials were substituted in the fireproofing spray. Steel will melt in an intense fire and asbestos slows the process.
Robert Szantner, a principle of Minoru Yamasaki Associates, the architectural firm that designed the World Trade Center, said asbestos was used in the construction.
"But the Port Authority, once they discovered that asbestos was a problem, put together a remediation program, that through the course of many years was eliminating most of the asbestos in the building," he told UPI. "However, there may be some minor areas that hadn't yet been completely upgraded to new fireproofing on the structural steel. So that should be the only remaining asbestos in the building. In proportion it should be fairly nominal."
Szantner said most of the dust seen in the air is gypsum board and pulverized concrete.
He said the structural steel can be accessed to clean off the asbestos and this was done for much of the building. "Judging from the program the Port Authority had, there shouldn't be much asbestos left in the building," he said.
One person close to the construction companies involved in the building of the towers has been involved in trying to determine the extent asbestos was used. The source told UPI, on the condition of anonymity, it appears asbestos had only been used in the first third of the first tower.
Emerging health concerns probably halted its use after that, the source said.
"It was being installed for probably the first third of the first tower, but since we were on the cusp of spray fireproofing with asbestos versus spray fireproofing without, because it was when asbestos started to become suspect, the Port Authority stopped its being installed and the rest of the building was installed without it," the source said.
"It's definitely safe to say it was not installed in all of both buildings." Richard Kielar, a spokesperson for Tishman Realty and Construction Co., the general contractor for the construction of the World Trade Center, said spray fireproofing would have been sprayed on structural steel, the perimeter columns, trusses that held up the slabs and also the interior core columns, in those portions of the two buildings where it was used. Kielar said it was proving difficult to obtain copies of the original plans, which are stored in hundreds of boxes.
Protracted exposure to asbestos fibers can cause scarring of the lung or asbestosis, lung cancer and cancer of the membrane covering the lungs, called mesothelioma.
According to Phillip Harber, professor and chief of occupational and environmental medicine at the University of California Los Angeles Medical School, "When you're looking at relatively low dose exposure, malignant mesothelioma is the thing you worry about." He said, however, exposure would need to go on for months or longer to cause the disease, which can take 20 to 30 years to appear.
Intense exposure for a brief period of time is not very likely to cause disease. "Asbestosis itself, lung scarring, that's not a real concern for people whose exposure was running out of the building or doing search and rescue operations. That takes a much higher dose," Harber said. Harber said it is important to measure the air in and around the World Trade Center, to stir it up and see if it creates a cloud that contains asbestos.
"If there is significant asbestos in the debris then it should certainly be handled appropriately to limit exposures," he said. "It's not so much the risk of running down the stairs, being in the area for an hour or five hours, but rather what is going to occur over the next two months or six months or whatever the cleanup is."
If the buildings had extensive asbestos in them, to do the cleanup safely is going to be more complicated. People doing the clean up would need to be appropriately protected. As the material is stirred up, it would be necessary to protect people who work or live in the area if significant levels of asbestos are detected, he added.
"It will be critically important to ascertain whether or not the material was present and secondarily to periodically monitor," he said. Patrick Breysse, associate professor of environmental health sciences at Johns Hopkins Bloomberg School of Public Health in Baltimore, Md., told UPI, "The big challenge in this case is in documenting what the airborne levels are." Occupational standards for traditional workplaces would keep exposures below 100 fibers per liter of air, Breysse said.
"I'd get some air samples out there and I'd monitor to see what the asbestos levels are, regardless of how much asbestos was in the building. Clearly some had to have stayed in the buildings," Breysse said. Workers could wear a monitoring device that weighs about a pound, and if recommended levels were exceeded, Breysse recommenced the workers be given respiratory protection.