757 Laboratory Safety

Mold and Fungi

The terms fungi and mold are often used interchangeably, but mold is actually a type of fungi. Concern about indoor exposure to mold has increased along with public awareness that exposure to mold can cause a variety of adverse health effects.

There are many thousands of species of mold and most if not all of the mold found indoors comes from outdoor sources. It seems likely to grow and become a problem only when there is water damage, high humidity, or dampness.

Molds produce and release millions of spores small enough to be air-, water-, or insect-borne. They can also produce toxic agents known as mycotoxins. Spores and mycotoxins can have negative effects on human health.

For those laboratory employees who are affected by mold exposures there can be a wide variation in how they react. Employees at greatest risk of health effects are individuals with allergies, asthma, sinusitis, or other respiratory conditions and weakened immune systems.

For more information on molds, read OSHA's publication 3304-04N 2006, Preventing Mold-Related Problems in the Indoor Workplace.

Plague

Plague is a disease well-known to humankind. Throughout history, in a series of epidemics, plague has claimed the lives of millions throughout the world. Infective fleabites are the most common mode of transmission, but direct human contact with infected tissues or body fluids of animals and humans also may serve as sources of infection. Human plague in the United States occurs as mostly scattered cases in rural areas effecting 10 to 20 persons each year. Globally, the World Health Organization (WHO) reports 1,000 to 3,000 cases every year.

Yersinia pestis, a documented laboratory hazard, is the causative agent of plague. It is a gram-negative, microaerophilic coccobacillus frequently characterized by a "safety pin" appearance on stained preparations from specimens. Specific biosafety procedures, including PPE, engineering controls, and additional work practices have been established for handling plague bacteria in laboratories.

Laboratory and field personnel should be counseled on methods to avoid fleabites and accidental autoinoculation when handling potentially infected live or dead animals. Special care should be taken to avoid generating aerosols or airborne droplets while handling infectious materials or when performing necropsies on naturally or experimentally infected animals. Gloves should be worn when handling potentially infectious materials including field or laboratory infected animals.

For more information on Plague, see OSHA's Plague Webpage.

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