Personal Protective Equipment

Personal protective equipment (PPE) refers to the respiratory equipment, garments, and barrier materials used to protect rescuers and medical personnel from exposure to biological, chemical, and radioactive hazards.

• The goal of personal protective equipment is to prevent the transfer of hazardous material from victims or the environment to rescue or health care workers.
• Different types of PPE may be used depending on the hazard present. The types of hazards addressed here include biological warfare agents (BWAs), chemical warfare agents (CWAs), and radioactive agents.
• The most common routes of exposure to these hazards include inhalation (breathing, from the air), skin contact, and ingestion (eating or drinking).

The use of personal protective equipment by the general public for protection against chemical and biological agents is controversial. Currently, the Centers for Disease Control and Protection (CDC) does not recommend that the public purchase respiratory protective equipment (gas masks) for several reasons.

• The likelihood that any person will be involved in a chemical or biological attack is extremely low.
• The CDC believes that gas masks may cause a false sense of security for the public.
• Masks that aren’t used properly or that do not fit well do not provide adequate protection and may in fact be harmful to one's health.

• Routes of exposure to biological warfare agents: Exposure is most likely to occur when victims breathe (inhalation) biological agents released into the air (aerosols). Very tiny particles are inhaled and gaun access to the body through the lungs. Mucous membranes or breaks in the skin also are vulnerable sites and require protection against biological warfare agents. However, skin contact does not pose a significant risk, because intact skin provides an effective barrier to all biological agents except trichothecene mycotoxins. Insignificant amounts of aerosolized particles stick to clothing or skin. It is difficult to get particles into the air once they have been released and landed (this is called secondary aerosolization). People are sometimes exposed by ingestion, which may occur with hand-to-mouth contact or by swallowing contaminated secretions. Follow these eMedicine links to anthrax, smallpox, and plague to learn more.
• Routes of exposure to chemical warfare agents: Exposure to chemicals and chemical warfare agents occurs by inhaling chemical gas or vapor. Exposure also occurs by direct contact of the eyes or skin to chemical vapor or liquid. Mucous membranes are particularly vulnerable, because moisture promotes the absorption of many chemicals. Ingestion is a minor route of exposure.
• Routes of exposure to radioactive agents: People exposed to beams of ionizing radiation (for example, patients receiving diagnostic X-rays) do not emit radiation and therefore pose no radiation danger to others. In the setting of an explosion, fire, or spill of radioactive material, however, victims can become contaminated with radiation-emitting material. External contamination occurs when radioactive material gets on a victim's clothing, skin, or hair. Victims also can become contaminated internally if radioactive material enters the body through the gastrointestinal tract, an open wound, or, less likely, inhalation of highly radioactive dust. In any situation, the goal of personal protective equipment is to prevent the transfer of radioactive material from the victim to the rescuer until the victim is decontaminated.

Civilian rescue or emergency care workers need personal protective equipment while they respond to contaminated environments or rescue contaminated people. Various types of emergency personnel require PPE, including first responders working in the hot zone (exclusion zone or contaminated area), emergency medical personnel involved in field decontamination (washing exposed people at the scene), and hospital personnel involved in decontamination at the hospital.

Doctors routinely use personal protective equipment to protect themselves against blood and body fluid exposure while caring for patients. They may use more specialized PPE when participating in prehospital response (usually as part of a specialized team) or when providing medical care to contaminated people at the hospital.

Many types of protective equipment are currently available, ranging from maximum protection with a positive pressure respirator and total body encapsulation to minimum protection with a simple surgical mask and a pair of latex gloves. These are the various types of protective respiratory devices and clothing.

Protective Respiratory Devices: The basic types of respirators are atmosphere supplying (self-contained breathing apparatus [SCBA], supplied-air respirator [SAR]) and air purifying respirator (APR).

• Self-contained breathing apparatus: SCBA consists of a full face piece connected by a hose to a portable source of compressed air. The open-circuit, positive-pressure SCBA is the most common type. This self-contained breathing apparatus provides clean air under positive pressure from a cylinder. The air then is exhaled into the environment. SCBA provides the highest level of respiratory protection.
• Supplied-air respirator: SAR consists of a full face piece connected to an air source away from the contaminated area via an airline. Because SARs are less bulky than SCBA, they can be used for longer periods. Supplied-air respirators are also easier for most hospital personnel to use. SARs, like self-contained breathing apparatus, provide a high level of respiratory protection.
• Air-purifying respirator: An APR consists of a face piece worn over the mouth and nose with a filter element that filters available air in the environment before inhalation. Three basic types of APRs exist: powered, disposable, and chemical cartridge or canister.
  • Powered air-purifying respirators (PAPRs) deliver filtered air under positive pressure to a face piece mask, helmet, or hood, which provides respiratory and eye protection. Nonpowered air-purifying respirators operate under negative pressure, depending on the effort of the wearer who is breathing in to draw air through a filter. Because PAPRs function under positive pressure, they provide high-level respiratory protection.
  • A variety of chemical cartridges or canisters, which eliminate a variety of chemicals including organic vapors and acid gases, are available.
  • Disposable air-purifying respirators usually are half masks, which do not provide adequate eye protection. This type of APR depends on a filter, which traps particles in the outside air. The use of a high-efficiency particulate air (HEPA) filter alone or in combination with a chemical cartridge enhances disposable APRs. For exposures to biological agents in the air, PAPRs with HEPA filters are most efficient, followed by elastomeric half-mask HEPA filter respirators and non-HEPA disposable APRs. All air-purifying respirators are limited by the adequacy of their face seals, which may not fully seal tightly. Accordingly, APRs do not provide adequate respiratory protection in environments immediately dangerous to life or health
• High-efficiency particulate air filter: HEPA filters remove very small particles with an efficiency of 98-100%, efficiently excluding most aerosolized biological warfare agent particles. HEPA filters are incorporated into a variety of protective respiratory devices including PAPRs and elastomeric half-mask respirators.
• Surgical mask: Surgical masks in a medical setting are designed to protect the sterile field of the patient from contaminants generated by the wearer. Although surgical masks filter out large-size particles in the air, they offer no respiratory protection against chemical vapors and little against most biological aerosols.

Protective Clothing: Most protective clothing is aimed at protection against chemicals and chemical warfare agents. Skin (intact, not damaged) provides an effective barrier against all biological warfare agents except the trichothecene mycotoxins. This toxin is capable of causing burnlike lesions on the skin.

• Chemical-protective clothing: Chemical-protective clothing consists of multilayered garments made out of various materials that protect against a variety of hazards. Because no single material can protect against all chemicals, multiple layers of various materials usually are used to increase the degree of protection. Aluminum-lined, vapor-impermeable garments increase the level of protection. Protection is maximized by total encapsulation (completely covering the wearer). An assortment of types of chemical-protective hats, hoods, gloves, and boot covers are used with the garments.
• Barrier gown and latex gloves: Barrier gowns are waterproof and protect against exposure to biological materials, including body fluids, but do not provide adequate skin or mucous membrane protection against chemicals. Latex gloves also protect wearers from biological materials but are inadequate against most chemicals. Barrier gowns, surgical masks, latex gloves, and leg and/or shoe covers (used in hospitals and in operating rooms) together are called universal precautions.

Military personal protective equipment refers to the protective respiratory devices, garment ensembles, gloves, and footwear covers worn by military personnel. The purpose is to protect military personnel from chemical, biological, and radioactive hazards, while enabling these people to accomplish their assigned missions. In all cases, military PPE used for chemical warfare exposures also protects against biological warfare agents.

• M40 mask: The M40 mask is a full-face chemical and biological protective mask that protects the respiratory tract, eyes, and mucous membranes in a manner similar to a nonpowered APR. Available in 3 sizes, the M40 mask combines the protective mechanisms of a charcoal filter against vapors involved in chemical warfare (especially nerve agents and blistering agents) and a HEPA filter against biological warfare particles in 1 screw-on filter canister. Maintenance of this filter canister is critical. Filter canisters must be replaced every 30 days, whenever filter elements are damaged physically or immersed in water, or when breathing becomes difficult while using them. Other features include 2 voicemitters for communication, optical inserts for visual correction, and a drinking tube.
• Battledress overgarments (BDOs): These are 2-layered chemical protective overgarments that contain an inner layer of activated charcoal to adsorb (bind with the agent, not absorb it) penetrating chemical liquids and vapors. Battledress overgarments also protect against biological warfare agents and radioactive alpha and beta particles. Available in 8 sizes in woodland or desert camouflage patterns, BDOs may be worn up to 24 hours in a contaminated environment. Contaminated battledress overgarments must be incinerated or buried.
• Chemical-protective gloves: Glove sets consist of a protective outer glove made out of butyl rubber and an inner glove for absorption of perspiration. Glove sets are available in 4 sizes and 3 thicknesses (7, 14, and 25 mL). Gloves may be worn for 12 hours in the contaminated environment. After visual inspection, gloves may be reused for another 12 hours. After use, gloves may be decontaminated and reused.
• Chemical-protective footwear covers: Single-sized butyl rubber footwear covers protect combat boots against all agents. Vinyl overboots also are available.
• Patient protective wraps: Also known as casualty wraps, these are chemical-protective and biological-protective wraps for casualties in contaminated environments in which personnel are unable to wear battledress overgarments . The top of the garment has a charcoal lining similar to the BDO, while the bottom is constructed of impermeable rubber. Breathing occurs through the permeable top, which functions as a protective respiratory mask.
• Wartime personal protective equipment for civilians: The chemical infant protective system is a semiclosed hoodlike system designed to protect infants in contaminated environments. This protective device delivers filtered air via a battery-operated blower. It is available for civilian use in Israel.

Civilian Personal Protective Equipment

The US Environmental Protection Agency has graded personal protective equipment into 4 levels based on the degree of protection provided. Each level consists of a combination of the protective respiratory equipment and clothing, which protects against varying degrees of inhalational, eye, or skin exposure.

• Level A consists of a self-contained breathing apparatus and a totally encapsulating chemical-protective (TECP) suit. Level A personal protective equipment provides the highest level of respiratory, eye, mucous membrane, and skin protection. See a rear view.
• Level B consists of a positive-pressure respirator (self-contained breathing apparatus or supplied-air respirator) and nonencapsulated chemical-resistant garments, gloves, and boots, which guard against chemical splash exposures. Level B PPE provides the highest level of respiratory protection with a lower level of skin protection.
• Level C consists of an APR and nonencapsulated chemical-resistant clothing, gloves, and boots. Level C personal protective equipment provides the same level of skin protection as level B, with a lower level of respiratory protection. Level C PPE is used when the type of airborne exposure is known to be guarded against adequately by an APR.
• Level D consists of standard work clothes without a respirator. In hospitals, level D consists of surgical gown, mask, and latex gloves (universal precautions). Level D provides no respiratory protection and only minimal skin protection.

Military Personal Protective Equipment

Military personal protective equipment also has been graded into levels, which are known as mission-oriented protective postures (MOPP). Seven levels of MOPP have been defined, ranging from MOPP ready (prepared to use MOPP gear within 2 hours) to MOPP 4 (maximum protection in protective respiratory mask and battledress overgarments). The higher the level of MOPP, the greater is the level of protection (and greater is the negative impact on individual performance).

Emergency care personnel who provide medical care to victims of hazardous incidents have the responsibility of first protecting themselves by wearing adequate protective equipment. Whenever possible, they will select the level of equipment based on the known properties of the hazard. When the type of hazard is unknown, they will assume a worst-case exposure and use the highest level of adequate protection.

The primary consideration in selecting appropriate equipment is whether it will be worn in the hot zone (exclusion zone or contaminated area) or in the warm zone (contamination reduction zone or area where decontamination of victims takes place). Because victims and equipment should be decontaminated thoroughly before leaving the warm zone, protective equipment is unnecessary in uncontaminated areas (except as noted here).

Hot Zone

The hot zone is immediately dangerous to life or health. Accordingly, level A personal protective equipment with self-contained breathing apparatus or supplied-air respirator is required for first responders or other personnel working inside the hot zone, where contact with hazardous materials is likely, including chemical gas or vapors, biological aerosols, or chemical and/or biological liquid or powder residue. Incidents occurring in enclosed spaces with poor ventilation increase the risk of inhalation.

Warm Zone

The warm zone is an uncontaminated environment into which contaminated victims, first responders, and equipment are brought. In classic HAZMAT (hazardous materials) response, the warm zone is adjacent to and upwind from the hot zone. However, experience with previous disasters indicates that contaminated victims capable of fleeing the hot zone are likely to bypass emergency medical services and go directly to the nearest hospital, in which case the warm zone may occur outside the emergency department or even inside the hospital.

Accordingly, the warm zone poses a risk of exposure to contaminated victims and equipment, which in turn depends upon the type and route of exposure. In general, early recognition of the type of exposure is based on the signs and symptoms that the victims show.

The protective equipment required depends on whether victims were exposed to a biological, chemical, radiological agent, or unknown agent or agents. The route of exposure may be inferred from the presence of contaminant on the clothing and skin of victims.

Vapor or aerosol exposure leaves no or minimal contaminant on victims, and material breathed into the lungs is not exhaled to contaminate others. Liquid or powder exposures may leave visible residue. For example, in the Tokyo subway sarin attack in 1995, about 90% of the victims exposed to sarin vapor reported to medical facilities by private or public transportation without contaminating others. Fortunately, secondary injury to hospital staff was minimal (mostly eye irritation) and did not require specific treatment. In a similar manner, handling victims exposed to biological aerosols poses little risk to emergency care personnel outside the hot zone.

• Known biological warfare agent hazards
  • Personnel handling victims contaminated with biological warfare agents (BWA) require respiratory protection. Skin protection is largely unnecessary, because BWAs are not active through unbroken skin (with the single exception of the mycotoxins).
  • Personnel handling victims who have been exposed to a known BWA aerosol are not required to wear protective equipment because secondary aerosolization of residual agent from clothing, skin, or hair is insignificant.
  • When victims are contaminated with a known BWA liquid or powder, level D (universal precautions) and PAPR with HEPA filter are required until decontamination is complete. Level C personal protective equipment and PAPR with HEPA filter may be considered if the residue on victims is suspected of containing mycotoxins.
• Known chemical warfare agent hazards
  • Personnel handling victims contaminated with chemical warfare agents (CWA) require respiratory and skin protection.
  • When victims are exposed to a known CWA gas at standard temperature and pressure (such as chlorine, phosgene, oxides of nitrogen, cyanide), no personal protective equipment is required, because victims cannot breathe out hazardous gas and harm others.
  • When victims are exposed to a known CWA vapor from volatile liquid (such as a nerve agent or blistering vapor), PPE is required, because responders may be exposed to low levels coming from the victims.
  • When victims are contaminated with a known CWA volatile liquid, level C PPE with PAPR and chemical cartridge is required until decontamination is complete. In general, level C PPE is used when the inhalation risk is known to be below levels expected to harm personnel and when eye, mucous membrane, and skin exposures are unlikely.
• Known radiation hazards
  • When victims are exposed to external radiation but not contaminated with a radiation-emitting source, no PPE is required. If any doubt exists whether victims or their clothing are contaminated, they should be surveyed with a Geiger-Müller counter.
  • When victims are contaminated externally with radioactive material (on their skin, hair, wounds, clothes), use level D PPE (for example, waterproof barrier materials, such as surgical gown, mask, gloves, leg, and/or shoe coverings; universal precautions) until decontamination is complete. Double layers of gloves and frequent changes of the outer layer help reduce the spread of radioactive material.
  • Handle radioactive materials with tongs whenever possible. Lead aprons are cumbersome and do not protect against gamma or neutron radiation. For this reason, experts currently recommend against their use when caring for a radiation-contaminated victim. Health care workers also should wear radiological dosimeters while working in a contaminated environment. The health care facility radiation safety officer usually supplies these devices.
  • When victims are contaminated internally with radioactive material, wear latex gloves when handling body fluids (urine, feces, wound drainage). The health care facility radiation safety officer or health physicist can determine when the amount of radioactivity in the victim’s body secretions has fallen to a nondangerous level.
• Unknown hazards (biological, chemical or both)
  • According to current US government (OSHA) regulations, level A PPE is required for personnel responding to an unknown hazard. Recommendations for hospital personnel are not yet clearly defined. SCBA in the hospital setting is more cumbersome to use than SAR. Some experts maintain that level C PPE with PAPR (with organic vapor cartridge and HEPA filter) provides adequate protection until decontamination is complete. Unfortunately, no single ensemble of PPE can protect emergency care personnel against all hazards.

By definition, the cold zone should be completely uncontaminated. Nevertheless, victims exposed to certain biological warfare agents may develop disease that can be transmitted to others. This situation then poses a risk of secondary spread to medical personnel. The type of protective equipment required depends on the route of transmission of these infectious diseases.

• Respiratory droplet/airborne particles
  • PAPR with HEPA filter provides the greatest degree of respiratory protection against biological-associated disease spread by respiratory droplet (such as smallpox or pneumonic plague) or airborne particles (possibly smallpox) when treating victims with obvious disease. Disposable HEPA filter masks also work.
  • Evidence exists that smallpox may be transmitted by airborne particles under certain circumstances. Some people develop a very dense rash and severe cough when infected with smallpox. These victims are also likely to have many lesions involving the mouth and throat. During bouts of severe cough, they may shed virus into the air. One well-documented episode of this form of transmission occurred at the Meschede Hospital in Germany in January 1970.
  • Medical personnel should wear latex gloves while handling the skin of people with smallpox, because smallpox may potentially be transmitted by contact with pox lesions that have not yet crusted over. The last naturally occurring case of smallpox was in 1977. The WHO declared the world free of smallpox in 1980. The risk of smallpox being used as a weapon of bioterrorism is considered small and theoretical at present. However, the CDC lists smallpoc as a "Group A" disease because it is easily disseminated and transmitted from person to person and results in high mortality rates.
• Blood or body fluid
  • While in contact with victims with biological-associated disease spread by blood or body fluid contact (hemorrhagic fever from Ebola, for example), level D PPE (standard precautions) is generally protective. Higher levels of protection may be necessary, however, if such victims have coughing or extensive bleeding.

The use of any type of personal protection equipment requires adequate training. The overall goals of training are to protect the wearer from physical hazards (biological, chemical, radioactive) and to prevent injury from improper use or equipment malfunction.

• Personal protection equipment has its limitations:
  • Takes time to put on: Level A PPE takes the longest time to put on.
  • Difficult to perform tasks while wearing the equipment: Some first responders or emergency care personnel may experience difficulty in performing some life-saving interventions.
  • Hard to move around while wearing the equipment: Mobility decreases with weight. Mobility also is limited by using a SAR, because the wearer must retrace his or her steps along the supplied air line to exit the hot zone.
  • Difficult to communicate: Someone wearing a face piece or mask is difficult to understand.
  • Hard to see: Face pieces also may limit the wearer's visual field.
  • Full protection suits become hot inside: Encapsulation and moisture-impermeable CPC material lead to heat stress.
  • Increased weight: Level A with SCBA is the heaviest PPE.
  • Psychological stress: Encapsulation increases the psychological stress to wearers and victims.
  • Can’t wear suits for long periods of time: Wearing level A PPE for longer than 30 minutes is difficult.
  • Limited oxygen availability: SCBAs only can be used for the period of time allowed by the air in the tank. APRs only can be used in environments in which the outside air provides sufficient oxygen.
• PPE also is associated with potential hazards or risks to wearers, as follows:
  • Improper use: Protective respiratory devices and CPC must be properly fitted, tested, and periodically checked before use.
  • Penetration: If the equipment does not fit properly, the hazardous agents may penetrate the equipment, and the wearer may become contaminated. Also, certain chemicals may break down the equipment, which would have to be replaced.
  • Recontamination: Wearers may become contaminated as they remove their equipment unless decontamination and removal protocols are followed carefully.