Ithaca, New York - Fewer than 4 percent of U.S. firefighters are women, despite almost half of female firefighter candidates passing physical ability tests, a study says.

Co-author Francine Moccio, director of Cornell University's Institute for Women and Work looked at the percentage of women in comparable jobs requiring strength and stamina or involving dirty or dangerous work such as drywall installers, loggers and welders and found women represented 17 percent of these workers.

However, 51 percent of paid fire departments have never hired a female firefighter and the New York City Fire Department has fewer than 0.25 percent women firefighters, the study says.

In addition, Moccio and her research team analyzed surveys from 675 firefighters from 114 departments in 48 states and interviewed 175 female firefighters in depth.

The researchers found that women firefighters are simply not being hired. When women are hired, the study found that 85 percent say that they were treated differently; 80 percent say they were issued ill-fitting equipment, 37 percent report that their gender creates barriers to career advancement; 50 percent feel shunned or socially isolated; and 37 percent are verbally harassed.

The findings were presented at the International Association of Women in Fire and Emergency Services meeting, in Phoenix.