Lab coats, hospital gowns and other protective garments may dispense a false sense of security to American health care workers. Deadly diseases like AIDS and hepatitis B may sneak through fabric to infect nurses, doctors, emergency room personnel, even research scientists.

Occupational Safety and Health Administration regulations require employers to provide protective clothing for workers who handle infectious body fluids. Under those standards, garments must prevent blood and other potentially hazardous fluids -- including air -- from reaching the worker.

"Although manufacturers have adopted standardized methods for testing barrier effectiveness of surgical gowns, they have not addressed other garment requirements, like linting and breathability," said Dr. Karen Leonas, a textile researcher in the University of Georgia College of Family and Consumer Sciences. "And the standards are somewhat ambiguous."

The lack of adequate products and product testing are critical concerns for employers in the '90s whose staffs handle potentially contaminated blood and other body fluids, she said.

"Most viruses and bacteria need carriers like liquids, dust particles, lint or skin cells to transport them from one side of the fabric to the other," she said. "An exception is the HIV virus, which a recent study showed can move through the fabric without the aid of a liquid."

Carriers move bacteria and viruses through seams, stitches and holes in the fabric. Some gowns are reinforced in the sleeves and chest areas, where fluids are most likely to spill or splatter.

Leonas is evaluating fabrics used in commercially available surgical gowns and other medical garments for permeability and repellency. To find out how well fabrics perform as barriers, she studies fiber content, filament size, pore size and shape, thread count, weight and the thickness of commonly used gowns.

Electron micrographs show clearly why some fabrics are better barriers than others. "You can see the large pore size in some patterns even though they look tightly woven to the naked eye," Leonas said.

Her absorbency tests show that water, synthetic blood, a saline solution, and alcohol react with fabrics in different ways. The fabrics absorb alcohol quickly, while the saline solution penetrates at a much slower rate.

In one experiment, bacteria were inoculated into saline solution. Some fabrics absorbed the saline solution but prevented the bacteria from penetrating to the other side. Because bacteria also can attach to small particles in the air, low-linting fabrics are most desirable. In fact, lint may fall into a wound, resulting in infection.

Although some reusable gowns worn in operating rooms are treated with a chemical to improve repellency, their effectiveness as barriers declines after repeated laundering. Some disposable gowns are effective, but they pose the same problem as other medical wastes: how and where to dispose of them safely.

Leonas said the key to improving the safety of the gowns is to reduce pore size and improve fabric repellency. And that will take the work of both textile researchers and medical scientists.

"Right now, most research for safer apparel is being done by medical experts who understand the bacterial and biological technology, but may not understand all of the textile and fabric technology," she said.

Leonas is working with Professional Health Care, a division of Kimberly-Clark Corp., which manufactures single-use operating room gowns. Her findings in that research may lead to the development of safer, more protective garments.

Although safety is critical, it is not the only consideration in garments for health care workers. Garments also must be lightweight, flexible and breathable to accommodate long hours in operating rooms or labs.

"Long hours of surgery call for a fabric that will stretch around bending elbows, and allow air to permeate and relieve perspiration," Leonas said. "Past studies show that overall comfort and attractiveness are important as well.

"A fabric must be developed that can satisfy all these needs," she said. And as health care workers continue their combat with deadly infectious agents, Leonas and others will help them suit up in apparel that will offer maximum protection.