Anthrax in the Workplace

Anthrax Matrix Pyramid

In October 2001, four workers died from inhalation anthrax and an additional 13 developed cutaneous or inhalational disease as a result of intentional terrorist activity. In most cases seen thus far, the disease was linked to unexpected workplace exposures to anthrax spores contained in letters mailed through the United States Postal Service. Fortunately, the number of workplaces contaminated with the spores has also been quite limited. Nevertheless, employers and workers are concerned about possible exposure to Bacillus anthracis in the workplace.

Risk Reduction Matrix

This matrix was developed to offer basic advice and suggest protective measures that OSHA believes will reduce the risk of exposure in light of current concerns about the presence of anthrax spores in the workplace. This matrix is not intended to establish a legal standard of care with respect to anthrax spores in the workplace. These recommendations do not impose and are not intended to result in the imposition of any new legal obligations or constraints on employers or the states.

Making Informed Decisions

This matrix is intended to help employers understand how to assess the risk of exposure to anthrax spores in their workplaces and to make the necessary decisions to successfully protect their workers from this exposure. The level of risk in any particular workplace is based upon factors such as:

  • current patterns of workplaces contaminated with anthrax spores;
  • the likelihood of the workplace being a target for Bacillus anthracis contamination;
  • the proximity of a workplace or workstation to areas known to be contaminated with anthrax spores;
  • the likelihood of the workplace receiving mail or other items from a contaminated facility;
  • any information provided by law enforcement or public health officials about the workplace's risk of receiving contaminated items;
  • the amount of mail the workplace receives;
  • the type of workplace - for example, a post office, bulk mail center, or public or private mail room where cross-contamination might be possible;
  • the potential that workplace operations and tasks could result in exposure if contaminated mail is received;
  • the use of high speed mail handling equipment, or other processes that might aerosolize anthrax spores during processing; or
  • any other information or analysis that would indicate the workplace might be contaminated with anthrax spores.

Limitations of this Guidance

Terrorist activity is unpredictable, and it is possible that releases of anthrax spores and workplace exposure will occur in locations not yet anticipated. The risk criteria presented here may change as our national understanding of the threat evolves. OSHA remains committed to helping employers protect their employees from the threat of bio-terrorism in the workplace and is working closely with other Federal agencies involved in responding to that threat in order to provide employers with the most up-to-date information and guidance available.

Explore the Pyramid

OSHA's Mission and Role

OSHA believes that it can best help employers and workers protect themselves by providing information and assistance that should help reduce employee exposure to, and risk from, anthrax spores. OSHA is also working with other Federal agencies and employers -- including the Centers for Disease Control and Prevention (CDC) and, within CDC, the National Institute for Occupational Safety and Health (NIOSH); the Federal Bureau of Investigation (FBI); the Environmental Protection Agency (EPA); and the U.S. Postal Service and Postal Unions - to make sure that the guidance OSHA gives is the best and most current information available.

How to use this Guidance

To help employers determine appropriate work practices and precautions, OSHA has divided workplaces and work operations into three risk zones, according to the likelihood of contamination with anthrax spores and employee exposure to them. These zones are called the green zone, the yellow zone, and the red zone.

Green Zone: workplaces where contamination with anthrax spores is unlikely.

Yellow Zone: workplaces where contamination with anthrax spores is possible.

Red Zone: workplaces where public health or law enforcement authorities have stated that contamination with anthrax spores has been confirmed or is strongly suspected.

We show these zones within the shape of a pyramid to represent how the risk appears to be distributed. Based on information currently available, contamination with anthrax spores and exposure to the bacterium are unlikely in the vast majority of American workplaces, represented by the green zone.

Employers should consider the factors listed above and use their knowledge of their own workplace, together with current information about the anthrax threat from law enforcement organizations and public health departments, to determine the zone that best describes their workplaces. After you make that determination, click on that zone on the pyramid below to see OSHA's recommendations for work practices and precautions that may reduce the risk of and worker concern about anthrax exposure in your workplace. For each zone, we point to sources of additional online information to help you understand and implement these protective measures.