Bioweapons

Biological Agents: Protective Clothing

Background

1. Non-state groups, lone actors, and even members of the medical community have committed bioterrorism and biocrime
   • Likelihood of amateurs using homemade equipment to successfully develop/deploy biological weapon of mass destruction is remote
   • Terrorists rely on explosives as weapon of choice
     • Aum Shinrikyo program and Al Qaeda demonstrate intentions to harness modern microbiology for malicious purposes
2. Guidelines for firefighters and other responders against biological agents
   • Recommendations for the Selection and Use of Respirators and Protective Clothing for Protection Against Biological Agents
3. Plan should include assessment of:
   • Hazard and exposure potential
   • Respiratory protection needs
   • Dermal protection needs
   • Entry conditions, exit routes
   • Decontamination strategies
4. DoD Policy
   • Use FDA-licensed, commercially available medical countermeasures (i.e., vaccines) to protect the health of U.S. forces from biological warfare threat agents
   • Employ IND medical countermeasures only when FDA-licensed products are unavailable and
   • There is a confirmed high risk to force health protection that necessitates consideration of IND product use
   • Only after an in-depth review and approval by
     • The Secretary of Defense of a request initiated by a Commander of a Combatant Command through the Chairman of the Joint Chiefs of Staff and
       • In coordination with the ASD(HA) (Assistant Secretary of Defense for Health Affairs)
       • The Under Secretary of Defense for Policy
       • The Secretary of the Army as the Executive Agent, and
       • The DoD General Counsel
   • In strict compliance with
     • A specific treatment protocol developed for the required indication that has been reviewed by the FDA and
     • Complies with the requirements of 21 C.F.R.
       • Including the requirement for informed consent and
       • Informed consent may be waived only by the President upon request by the Secretary of Defense and
       • Only under specified conditions
     • If a presidential waiver of informed consent is approved, then
       • DoD Components must conduct ongoing monitoring and adhere to periodic reporting as required by the President
       • The Secretary of Defense shall notify
         • Congress, and the public by Federal Register notification, as soon as practicable
         • The President and the FDA Commissioner of any changed circumstances concerning the need to waive informed consent, and
       • The waiver of informed consent terminates after 1 year or when no longer needed—whichever is earlier
   • Vaccinate “at-risk” personnel against validated biological warfare threat agents
     • In sufficient time for them to develop immunity before deployment to high-threat areas
   • Integrate and prioritize efforts for vaccine research, development, testing, evaluation, acquisition, and stockpiling and
     • To improve existing vaccines against validated biological warfare threat agents
   • Develop a capability to acquire and stockpile adequate quantities of vaccines
     • To protect the programmed force against all validated biological warfare threats

Rationale

1. Biological weapons may expose workers to bacteria, viruses, or toxins as fine airborne particles
   • Biological agents are infectious through ≥ 1 of the following mechanisms of exposure (depends on agent):
     • Inhalation (infection through respiratory mucosa or lung tissues)
     • Ingestion
     • Contact with mucous membranes of eyes or nasal tissues
     • Penetration of skin through lesions/abrasions
2. Biological agents, as liquid or solid organic airborne particles, behave the same in the air as inert or inorganic particles
   • Because they share the same aerodynamic characteristics
3. Because biological weapons are particles
   • Will not permeate materials used in construction of respirators or protective clothing the same way that some chemicals can permeate through them
     • However, biological particles potentially can penetrate through seams, closures, interfaces, pores, and gaps in protective apparel
     • Careful attention to properly selected, assembled and fitted personal protective equipment (PPE) is essential to ensuring necessary protection for first responders
4. Some devices used for intentional biological terrorism may have the capacity to disseminate large quantities of biological materials in aerosols
   • High levels of protection (i.e., level A ensembles) will be necessary when hazards and airborne concentrations are either unknown or expected to be high
   • PPE providing lower levels of protection (i.e., level B or C ensembles) are generally allowed once conditions are understood and exposure are determined to be at lower levels
5. Chemical, biological, radiological, and nuclear (CBRN) NIOSH-approved respirators in conjunction with protective ensembles certified to National Fire Protection Association (NFPA) standards are recommended for responders
   • In situations where the hazard potential from a potential terrorist event exists
   • Respirators/protective ensembles certified for CBRN-rated protection have been evaluated with warfare agents for resistance against permeation and penetration of the materials used in their construction
     • For example, rubber, elastomeric, barrier, and selectively permeable materials
   • CBRN respirators provide a high level of protection against airborne hazards when
     • Properly fitted to the user’s face
     • Properly used in an Occupational Safety and Health Administration (OSHA)-compliant respiratory protection program external icon
6. During an intentional release of a biological agent
   • Concurrent or secondary release of other types of hazards, such as a chemical, may occur
   • Therefore, when selecting appropriate levels of PPE
     • Information regarding potential of exposures to non-biological hazards should be factored into any selection decisions
7. Appendix B of the HAZWOPER standard defines the OSHA/EPA Protection Levels A, B, and C as follows (View image)
   • Level A—To be selected where the hazards are unknown or unquantifiable or when the greatest level of skin, respiratory and eye protection is required
   • Level B—The highest level of respiratory protection is necessary, but a lesser level of skin protection is needed
   • Level C—The concentration(s) and type(s) of airborne substances is known and the criteria for using air-purifying respirators are met

Undefined Situation

1. Use NIOSH-approved, CBRN SCBA in conjunction with a Level A, protective suit in responding to suspected incident is unknown or the event is uncontrolled:
   • Type of airborne agent
   • Dissemination method
   • If dissemination via aerosol-generating device still occurring or it has stopped but no information on duration of dissemination, or what exposure concentration might be
   • Other conditions may present a vapor or splash hazard

Defined Situation

1. Use a Level B protective ensemble (certified to NFPA 1994 Class 2, NFPA 1992, or NFPA 1971 CBRN protective ensembles if available as first choice) if exposed/enclosed NIOSH-certified CBRN SCBA if:
   • Suspected biological aerosol no longer being generated
   • Other conditions may present splash hazard
     • **Note: NFPA 1994 Class 4 does not have a requirement to provide limited protection against liquid or chemical hazards
2. Use a level C protective ensemble (certified to NFPA 1994 class 3 or 4 or certified as NFPA 1999 protective ensemble if available as first choice) with
   • CBRN full facepiece APR or CBRN full facepiece powered air-purifying respirator (PAPR) when it can be determined that:
     • The suspected biological aerosol is no longer being generated
     • The biological agent and hazard level have been defined
     • Dissemination was by a letter or package that can be easily bagged

After risk assessment downgraded

1. When a risk assessment has been conducted by qualified safety and health experts use alternate PPE, including
   • Non-CBRN level C protective ensembles with
     • 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

References

1. DHHS (NIOSH). Guidance on Emergency Responder Personal Protective Equipment (PPE) for Response to CBRN Terrorism Incidents. Available at: https://www.cdc.gov/niosh/docs/2008-132/pdfs/2008-132.pdf?id=10.26616/NIOSHPUB2009132. [Accessed October 2023]
2. CDC. Emergency Preparedness and Response: Bioterrorism. Available at: https://emergency.cdc.gov/bioterrorism/prep.asp?CDC_AA_refVal=https%3A%2F%2Femergency.cdc.gov%2Fbioterrorism%2Fresponders.asp. [Accessed October 2023]
3. Ready.gov. Chemicals and Hazardous Materials Incidents. Available at: https://www.ready.gov/hazmat. [Accessed October 2023]
4. In: Bozue J, Cote CK, et al; (eds). Medical Aspects of Biological Warfare. Office of the Surgeon General, Borden Institute US Army Medical Dept Center and School: Fort Sam Houston, TX, 2018
5. In: Institute of Medicine (US) and National Research Council (US) Committee on Accelerating the Research, Development, and Acquisition of Medical Countermeasures Against Biological Warfare Agents; Joellenbeck LM, Durch JS, Benet LZ; (eds).
   Washington (DC): National Academies Press (US); 2004.

Contributors

1. Ho, Nghia, MD

Updated/Reviewed: October 2023