Recently, 3M has received a number of inquires from employers and workers regarding the appropriate respirator recommendations for potential exposures to biological agents, such as Bacillus anthracis (the spores that cause the disease called Anthrax) in their facilities.



Summary
All EC type approved (CE marked) particulate respirators will help reduce exposures to biological aerosols such as B. anthracis, the bacteria that causes Anthrax. However, no safe exposure levels (i.e. the amount you can inhale without adverse health effects) have been set for biological aerosols, including B. anthracis.

Therefore, while respirators can reduce exposures they cannot eliminate the risk of contracting infection, illness, or disease. Respirators may help protect your lungs, however, it will not prevent entry through other routes such as the skin which would require additional personal protective equipment (PPE).

Currently, there are no published respirator guidelines for B. anthracis; therefore, it is up to the employer to select the level of respiratory protection that is appropriate for their situation.

Frequently Asked Questions
Following are answers to some frequently asked questions regarding respirator usage for potential occupational exposures to Bacillus anthracis.

Q. When would a respirator be appropriate to help protect myself from B. anthracis?

A. A properly fitted respirator can only help reduce exposures when used immediately prior to and during the release of Bacillus anthracis spores. Unfortunately, in the case of terrorist activity it is unlikely that you would have warning or knowledge of your exposure until symptoms started to appear in infected people. Once anthrax symptoms appear, a respirator will not be effective in helping to prevent anthrax disease.

To reduce the exposure to B. anthracis spores a respirator must be worn at all times during the potential exposure period and at all times while in a contaminated area. To wear a respirator continuously (i.e., whole work day) to prevent the inhalation of B. anthracis spores would be impractical since you still must eat, drink and effectively communicate during the workday. For certain workers or first responders, continuous wear of a respirator during the exposure period may be feasible.

Q. What are the limitations of using respirators for potential exposures to B. anthracis?

A. Before selecting respiratory products for biological agents, such as B. anthracis, there are important considerations you must be aware of. The airborne concentration of these agents will be unknown; therefore it may be difficult to select the most appropriate respirator.

In addition;

• Respirators reduce, but do not eliminate exposure to B. anthracis or the possibility of developing anthrax related disease, illness or infection. There may be no obvious warning in the event of a release of B anthracis.
• Respirators may help protect your lungs, however, it will not prevent entry through other routes such as the skin which would require additional personal protective equipment (PPE).
• Without proper decontamination, materials could create a hazard by bringing the spores into areas thought to be uncontaminated.
• EC type approval does not currently test/ certify respirators for use against B. anthracis.
• Exposure limits have not been set for biological aerosols such as B. anthracis.
  

It is also important to understand that respirators are designed for occupational/ professional use by adults who are properly trained in their use and limitations.

• Proper fit of the respirator to the face is extremely important. If it does not fit properly, you will be exposed to the B anthracis you are trying to filter.
• Individuals wearing tight fitting face pieces must be clean-shaven at all times when wearing respirators.
• Some people may find a negative pressure respirator difficult to breathe through and should consult with a physician prior to use.
• In some situations or for some individuals a powered air respirator may be more appropriate than a negative pressure air filtering device.

Q. Will a respirator prevent me from inhaling B. anthracis spores?

A. Respirators reduce, but do not eliminate exposure to airborne contaminants. Filter efficiency, fit of the respirator, and wear time all play a role in effectively reducing respiratory exposure to B. anthracis spores.

Q. Is B. anthracis filtered differently from other particles found in industrial situations?

A. Biological agents such as B. anthracis are particles and can be removed by particulate filters with the same efficiency as non-biological particles having the same physical characteristics (size, shape, etc.) However, unlike most industrial particles there are no exposure limits (such as OELs) established for biological agents such as B. anthracis.

Q. What class of filter efficiency is capable of filtering out B. anthracis spores?

A. According to leading experts in this field (eg Centre for Disease Control (CDC) USA) the typical size of B. anthracis spores is between 1 – 5 microns. CE approved filtering facepieces or filters for use with reusable facepieces are tested using particles of a smaller size range, with a mass mean diameter of 0.6 microns.

CE approved filtering facepiece respirators are classified according to the filter efficiency and the total efficiency of the device when worn.

Therefore an EN149:2001 FFP3 respirator is classified as at least 98% efficient for particles in the range 1 to 5 microns.

A particulate filter meeting EN143:2000 P3 when fitted to a reusable half mask meeting EN140:2000 is also classified as at least 98% efficient for particles in the range 1 to 5 microns.

[Generally leading experts are suggesting the use of an FFP3 or P3 device, however some countries have national guidelines, which may be different and which should be followed.]

Q. How important is proper fit of a respirator when trying to filter out B. anthracis?

A.While a respirator may be equipped with filter media to effectively capture airborne particles, the particles may enter the wearer’s breathing zone inside the respirator through leaks around the facepiece. Proper fit along with the appropriate filter is critical in reducing exposures to B. anthracis.

Whether you select a filtering facepiece respirator or a reusable respirator with replaceable filters, the wearer must obtain a satisfactory fit. Fit testing using either a qualitative or quantitative fit test method is recommended.

Q. Are there regulations or exposure limits governing occupational exposures to B. anthracis?

A.Exposure limits and regulations governing responses to biological agents such as B. anthracis have not been established. However, National Health and Safety regulations should be followed when applicable. When a facility decides to make respiratory protection part of its emergency management or response plan, it is essential that a full respiratory protection programme be implemented. This programme should be administered by a trained individual and include written standard operating procedures, user training, respirator maintenance procedures and proper fitting of respirators to all users.

Q. Are there any respirators certified for B. anthracis exposures?

A. Currently there is no testing/approval process for specific biological agents such as B. anthracis.

In Europe, Personal Protective Equipment (PPE) – including Respiratory Protective Equipment (RPE) - must be approved under European Directive 89/686. Both negative pressure and powered air respirators which are approved, will as part of the approval process, have been tested to a harmonised European Standard and certified for use against particles and/or gases and vapours.

Q. How does a respirator’s protection factor relate to choosing a respirator for B. anthracis exposures?

A. It is important to understand that since the safe level of exposure to B. anthracis spores is not established, there is no assurance that any respirator will mitigate or prevent anthrax infection or disease. Respirators are traditionally selected using the airborne concentration of the contaminant, the exposure limit of the contaminant and the nominal protection factor of the respirator.

In the United Kingdom, CE approved respirators have a nominal protection factor (NPF) and an assigned protection factor (APF*). The APF indicates by how much the respirator will reduce a wearer’s exposure assuming they have a good fit and are trained in how to wear the device correctly.

Currently there are no established methods for measuring the concentration of B. anthracis spores in the air, nor have exposure limits been determined. Therefore, the traditional respirator selection method cannot be uniformly applied.

The following table lists common configurations of respirators, the assigned protection factors (APFs) and the 3M™ Respirator product numbers:

Filtering Facepiece Respirator FFP2
APF = 10

8810, 8822, 8825, 9320, 9322
more...

Reusable half mask + P2 filters
APF = 10

6000/7000 Series half mask
+ 2125 filter
more...
Filtering Facepiece Respirator FFP3

Reusable half mask + P3 filters
APF = 20

6000/7000 Series half mask
+ 2135 filter
more...

Reusable full face mask + P3 filters
APF = 40

6000/7000 Series full face mask
+ 2135 filter
more...

Powered Air Respirators
APF = 20

Jupiter Turbo Unit and
100 Series Hood
+ P3 Filters
more...

Facilities or personnel who are choosing respirator for possible exposure to B. anthracis need to understand not only the filtration characteristics of the respirator but also the protection factor of the respirator. The goal of using a respirator is to reduce the exposure to an acceptable level that will not adversely affect the wearer.

The protection factor predicts the potential reduction in exposure that would occur if one were properly wearing that type of respirator. In the case of B.anthracis the exposure level and level that does not cause an infection in the wearer will probably be unknown. A higher protection factor will provide greater exposure reduction when the respirator is used properly and fitted to the individual. You will need to select the appropriate facepiece for your workers that corresponds to the level of exposure reduction that you feel is appropriate.

*Assigned Protection Factor - From BS4275 1997, A guide to Implementing an Effective Respiratory Protective Device Programme.

Q. When would a respirator with a higher assigned protection factor be needed for exposure to B. anthracis spores?

A. Respirators will help reduce exposures to B anthracis, but they cannot be guaranteed to eliminate exposure or the risk of contracting anthrax related disease, illness, or infection. A respirator with a higher assigned protection factor will provide a greater exposure reduction when the wearer has been trained in how to fit the respirator properly. You will need to select the appropriate facepiece that corresponds to the level of exposure reduction that you feel is appropriate for your situation.

Q. What type of respirator would be most appropriate to wear for B. anthracis exposures in a healthcare setting?

A.

Triage
This area would typically encounter patients recently exposed to B. anthracis or those experiencing symptoms of the disease. In some cases the healthcare facility has already devised a plan that includes appropriate respiratory protection for the attending medical personnel. Personnel who work in this area should consult with local emergency response agencies to establish procedures for treating suspected cases of B. anthracis exposure. In many cases the patient will be decontaminated and treated outside of the healthcare facility. It is important to keep in mind that while a recently exposed patient may carry spores on their person or clothing, the disease itself is not communicable between people.

Patient Care
Anthrax is not contagious and patients who have been admitted to the hospital would be expected to be decontaminated prior to admission. Personnel working in patient care should consult health authority guidance and follow local requirements.

Q. Will a surgical mask provide protection from inhaling B. anthracis spores?

A.Surgical masks are designed to protect patients or wound sites from exhaled aerosols from the mask wearer. They are not designed to provide respiratory protection to the wearer. Unlike an approved respirator, many surgical masks contain no or low efficiency filter media and do not form a tight seal against the face. However, there are some surgical masks that have been designed to pass European respirator certification requirements.

Users should consult the surgical mask manufacturer for advice on suitability of the product for this application.

Q. Is other personal protective equipment (PPE) needed in addition to a respirator?

A. Anthrax infections can occur if B. anthracis spores enter the body via:

• inhalation
• abraded skin
• ingestion

It is important that when choosing personal protective equipment that all these routes of entry are protected.

Q. What if I have a beard and want to wear a respirator for B. anthracis exposures?

A. A tight sealing respirator, one where the sealing surface contacts the face, will not provide an adequate seal when placed over facial hair. A bearded worker will typically require a respirator where the facial hair does not interfere with the face seal of the headpiece. In many instances this will consist of a powered air respirator with a hood or helmet.

Q. How long will I need to wear a respirator for B. anthracis exposures?

A. To reduce the exposure to B. anthracis spores a respirator must be worn at all times during the potential exposure period and at all times while in a contaminated area.

Q. Why can’t 3M just tell me what respirator I need to use for protecting myself from B. anthracis?

A. Procedures for selecting proper respiratory protection are directed by requirements set by government agencies. In the absence of such requirements, 3M is unable to make appropriate recommendations because the airborne concentrations and safe levels of exposure to B. anthracis are unknown. It is up to each facility or individual, and not 3M, to determine which level of respiratory protection and respirator model will be used in its facility for occupational exposures to B. anthracis.

Q. Where can I find additional information on Anthrax?

A.
The following web sites contain additional information on Anthrax:

Centers for Disease Control and Prevention
http://www.cdc.gov/

World Health Organisation
http://www.who.int

Department of Health
http://www.doh.gov.uk/

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