| Health | House | News | Basics | Victims | Resources |
Fiberglass, sick buildings linked by Cornell researchers
By Robert Horowitz"A survey of sick building syndrome complaints in nine buildings was conducted. Airborne pollutants and ambient conditions were not correlated with sick building syndrome complaints. There was a significant correlation between man-made mineral fiber counts in settled dust and sick building syndrome complaints.” —from the study abstract
Sick Building Syndrome (SBS) occurs when a number of workers in an office building experience a variety of conditions, including eye, nose, throat and skin irritation, headaches, lethargy and respiratory problems. Doctors are often unable to explain the malaise, and it may be attributed to stress or low morale.
Although no one has proven the causes of sick building syndrome, in 1994 three researchers at Cornell University found a link between man-made mineral fibers in the settled dust in sick buildings, and the number of SBS symptom complaints by workers.
SBS has become more common place as the airtight office buildings built in the 60s, 70s and 80s age. The Cornell study, by Alan Hedge, William Erickson and Gail Rubin, was presented at the 6th International Conference on Indoor Air Quality in Helsinki, Finland.
Previously, researchers linked the amount of dust in offices and SBS, but few offices are monitored for man-made mineral fibers (MMMF), and the MMMF factor was unexplored.
“Although many people assume sick building syndrome is related to gaseous air pollutants (such as smoking), many studies, including ours, have been unable to find the link,” said Hedge, an associate professor of design and environmental analysis at Cornell. “When we look at MMMF, however, we find much higher reports of SBS where MMMF are high. These findings strongly suggest that MMMF may be a major player in SBS.”
Shortly after the study was released, one manufacturer of the type of ceiling tiles implicated in Hedge’s study sent two people to visit Hedge and politely discourage him from continuing this vein of research. The North American Insulation Manufacturers’ Association, predictably, labeled Hedge’s work flawed and unscientific.
Hedge, whose studies included more than 4,000 workers in 27 buildings scattered around nine states, previously investigated relationships between tobacco smoke, carbon monoxide, carbon dioxide, formaldehyde, temperature and humidity on sick buildings, but found no correlation. The idea for studying mineral fibers came from a woman working in one of the sick buildings under study. She kept a small air filter on her desk, and asked Hedge to study what is trapped. Hedge traced the fibers he found in the desktop filter to ceiling tiles over her head.
This study was supported by the Center for Indoor Air Research in Maryland; however, Hedge had not identified funding to continue his research. He does hope to continue because, after 10 years of searching, he is convinced he has finally found an important factor behind SBS.
“I have a very, very strong hunch we have hit upon something of significance,” he said. “I don’t think it’s purely a fluke that we are seeing some association here. There is enough circumstantial evidence that (mineral fibers) are a variable one should look at seriously. It’s clear there is something going on in the dust in these buildings.”
A logical next step would be to standardize ways of analyzing the content of settled dust in buildings, said Hedge. In Sweden, he added, they are experimenting with ways to measure dust accumulation on the human face.
For this study, Hedge sampled dust atop file cabinets and desks, and used scanning electron microscopy to analyze the samples. High-volume air pumps were run for 12 hours at night (because of the noise), and the filters were scanned using the same method. Workers sitting nearest the sample sites were given questionnaires regarding the frequency of occurrence of 15 sick building symptoms.
The only relationship which was found was between the initial sampling of settled dust and reports of sick building symptoms. It is possible, said Hedge, that the air filter pumps run at night may have actually cleaned the air to the point where some workers symptoms were alleviated.
Computer monitors create electrostatic fields which may attract irritating fibers and dust particles, Hedge suggests, and analysis of the dust from computer screens seems to back that up. This could explain why people who spend the most time with computers report more SBS symptoms. Also, the heat generated by computers and monitors may dry the air around the worker, reducing the ability of the eyes to flush away fibers.
The phenol-formaldehyde binders used on many mineral fiber products also appear to attract dirt, dust and other chemicals, added the Cornell researcher. When you inhale those, you have a “direct route for getting some very nasty chemicals into the body,” he said. The fiber acts like a spear to help the substance permeate the body’s defenses.
“Many of these fibers are not pristine glass fibers,” said Hedge, “they’re covered in grunge.”
With slag-based mineral fibers being emitted by ceiling tiles, and glass fibers being emitted by insulation, ventilation ducts, ventilation system filters and room divider panels, and perhaps other sources, buildings are constantly shedding mineral fibers into the air, said Hedge. Simply removing ceiling tiles or insulation might not fix the problem.
Hedge recalled a conversation with a ceiling tile salesperson, who noted that American-made ceiling tiles were not allowed to be sold in Europe because they are softer and shed more mineral fibers than European-made tiles.
Air filtration systems should be used in offices whenever possible, Hedge said, in addition to a rigorous office-cleaning regimen to alleviate SBS symptoms. Because mineral fibers are so small; however, vacuums may stir up more mineral fiber dust than they remove from the office.
Vacuums built into buildings, which are more common in Australia and Europe than in the U.S., seem to have advantages in removing MMMF from the office.
“Chances are SBS is triggered by a range of factors, just like most other illnesses,” concluded Hedge. “People who report SBS symptoms are being exposed to real irritants, but in many cases they are evidently not from gases in the air. Rather, air can be filthy with fibers and particulates that are not now being measured or considered.”
