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NIOSH Publication No. 2009-132:Recommendations for the Selection and Use of Respirators and Protective Clothing for Protection Against Biological Agents |
April 2009 |
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From the National Institute for Occupational Safety and HealthThe approach to any potentially hazardous environment, including one with biological hazards, must be made with a plan that includes an assessment of hazard and exposure potential, respiratory protection needs, dermal protection needs, entry conditions, exit routes, and decontamination strategies. Plans involving a biological hazard should be based on relevant infectious disease or biological safety recommendations by the Centers for Disease Control and Prevention (e.g., http://emergency.cdc.gov/bioterrorism) and other expert bodies including emergency first responders, law enforcement, and public health officials. The need for pre/post exposure treatment of first responders with antibiotics, vaccination, or other medications should be determined in consultation with licensed medical personnel. This document is based on current understanding of the potential agents and existing recommendations for biological aerosols and is oriented toward acts of terrorism. The recommendations provided here do not address and are not applicable to controlled use of biological agents in biosafety laboratories. For information on precautions in the laboratory settings, please consult http://www.cdc.gov/od/ohs/biosfty/biosfty.htm. NIOSH is providing the recommendations in this document on the basis of the following considerations:
Guidance and Standards Associated with the Selection and Use of Protective Clothing and RespiratorsRespiratory protection and other PPE should be used in the context of a comprehensive program or incident command system that provides for a safety and health program. The program should contain the following elements:
When using respiratory protection, the type of respirator is selected on the basis of the hazard and its airborne concentration. Recommendations for selection of respirators can be found in the NIOSH Respirator Selection Logic 2004 [DHHS (NIOSH) Publication No. 2005-100] (http://www.cdc.gov/niosh/docs/2005-100/default.html). Additionally, guidance specific for CBRN incidents can be found in the NIOSH document Guidance on Emergency Responder Personal Protective Equipment (PPE) for Response to CBRN Terrorism Incidents [DHHS (NIOSH) Publication No. 2008-132] at http://www.cdc.gov/niosh/docs/2008-132/pdfs/2008-132.pdf For a biological agent, the air concentration of particles will depend upon the method used to release the agent, the initial amount of agent in the dispersal device, the particle size (very small particles will remain suspended in the air for prolonged periods, while large particles fall more quickly out of the air), and the elapsed time since the release. Secondary re-aerosolization generated from disturbing the contaminated area may contribute to an increase in particle concentration in the air. NIOSH-approved CBRN self-contained breathing apparatus (SCBA), which many first responders currently use for entry into potentially hazardous atmospheres, will provide responders with respiratory protection against biological exposures associated with a suspected act of biological terrorism. When site concentrations allow for the use of lower levels of protection, NIOSH-approved CBRN full facepiece air-purifying respirators (APRs) or CBRN full facepiece powered air-purifying respirators (PAPRs) may be used. Protective clothing, including garments, gloves and booties, also are necessary for the response to a suspected act of biological terrorism to reduce exposures to potential dermal, chemical, and physical hazards. Protective clothing must have physical performance properties adequate for the mission (e.g. tensile strength, puncture resistance, seam breaking strength, abrasion resistance). Protective clothing is used to prevent skin exposures and/or contamination of other clothing. The type of protective clothing needed will depend upon the biological agent, concentration, route of exposure, and anticipated work operations. NFPA 1994 Standard on Protective Ensembles for First Responders to CBRN Terrorism Incidents (2007 Edition), NFPA 1991 Standard on Vapor Protective Ensembles for Hazardous Materials Emergencies (1995 Edition), NFPA 1999 Standard on Protective Clothing for Emergency Medical Operations (2008 Edition) are nationally accepted and Department of Homeland Security (DHS)-adopted performance standards. Protective clothing ensembles certified to these standards should be the first choice when selecting protective clothing for protection against biological agents. Ensembles certified by these standards may be used to meet the applicable level of protection (i.e., A, B, C, and D) outlined by OSHA in the Hazardous Waste Operations and Emergency Response (HAZWOPER) standard, Appendix B. There are also other protective ensembles and clothing items that meet OSHA's specifications available on the market that will provide protection to biological agents. Detailed information on the NFPA standards in relationship to CBRN terrorism events can be found at http://www.cdc.gov/niosh/docs/2008-132/pdfs/2008-132.pdf NFPA 1999 Standard on Protective Clothing for Emergency Medical Operations, 2008 Edition specifies design, performance and certification requirements for protective clothing, including garments, helmets, gloves, footwear, and face protection devices used by emergency medical responders and medical first receivers. This standard includes requirements for a multi-use emergency medical protective ensemble providing minimum protection for upper and lower torso, head, hands, foot and face protection from only biological agents. Protective ensembles certified to requirements in NFPA 1999 should be considered for protection against biological agents. Recommendations for the Selection and Use of Protective Clothing and Respirators Against Biological Agents Resulting from a Suspected or Known Terrorism EventThe recommendations for personal protective equipment, including respiratory protection and protective clothing, are based upon the anticipated level of exposure risk associated with different response situations, as follows:
When a risk assessment has been conducted by qualified safety and health experts, responders may use alternate PPE, including non-CBRN level C protective ensembles with a full facepiece particulate respirator (N100 or P100 filters) or PAPR with high efficiency particulate air (HEPA) filters, in conjunction with disposable hooded coveralls, gloves, and foot coverings as appropriate. In certain specialized situations, half-mask filtering facepiece respirators in conjunction with reduced levels of dermal protection may be considered, but it should be recognized that this level of PPE may not provide sufficient exposure reduction for many situations. Several parameters must be assessed when making a decision to downgrade the ensemble. These include knowledge of the source and extent of contamination, the level of uncertainty in the risk assessment, specific activities to be conducted, investigator experience, contingency/backup plans, length of time in the contaminated area, provision for immunization and post-exposure prophylaxis, etc. A decision of this nature should be carefully evaluated and made by industrial hygiene, safety, and medical personnel in conjunction with the incident commander and other appropriate public health authorities. NIOSH recommends against wearing standard firefighter turnout gear into potentially contaminated areas when responding to reports of terrorist activities involving biological agents, provided there are no other hazards that would require turnout gear. Proper decontamination of protective equipment and clothing will ensure that any particles that might have settled on the outside of protective equipment are removed before taking off gear. Decontamination sequences currently used for hazardous material emergencies should be used as appropriate for the level of protection employed and agent encountered. For example, PPE can be decontaminated using soap and water, and 0.5% hypochlorite solution (one part household bleach to 10 parts water) with an appropriate contact time can be used. Note that bleach may damage some types of firefighter turnout gear (one reason why it should not be used for biological agent response actions). After taking off gear, response workers should shower using copious quantities of soap and water. Bleach should not be used to decontaminate response workers. Note that all NFPA 1994 ensembles are intended to be disposable after a single exposure use. |
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