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Koenig_and_Schultz_s_Disaster_Medicine_Ch_13.pdf

Personal Protective Equipment

Paul D. Kim, Frank J. Denny, and Sarah J. Salk-Pope

OVER V IEW

Following terrorist attacks such as the September 11, 2001 events in the United States, governments around the world at local, state, and federal levels placed increased emphasis on prepared- ness efforts. Vendors capitalized on this heightened attention by embarking on aggressive marketing campaigns flooding mar- ketplaces with advertisements for disaster survival kits, survival manuals, evacuation plans, instruction manuals on protecting families during a terrorist attack, and information on “the very best” personal protective equipment (PPE). However, as the time interval since the latest disaster increases, both public and gov- ernment interest in being prepared tend to fade. For example, in the United States, at the time of this writing, there is no federal law requiring state and local officials to plan for the evacuation of the sick, elderly, disabled, or impoverished. Ironically, pets are more protected as both houses of the U.S. Congress passed bills that require local governments to plan for the evacuation of pets.1

Nonetheless, some progress is being made in the area of PPE. PPE is being considered by many organizations and agencies.

These agencies are purchasing and supplying equipment for the protection of the workforce from possible attacks and threats uncovered through a hazards vulnerability analysis. Numerous pitfalls, obstacles, and confusing directions exist regarding equip- ment selection and indications for use in protecting individuals from a possible unknown hazard. The goal of this chapter is to provide the most complete, up to date, comprehensive informa- tion so an informed decision can be rendered for each unique work environment and potential threat.

STATE OF THE ART

PPE as a means to protect human beings from hazardous mate- rials has been an evolving science throughout history. Much of what is now used in the civilian sector has been developed by the military as a result of warring factions using whatever pro- tective means they could develop to counter hazardous materials

used by opposing forces to gain an advantage. Therefore, any discussion on PPE requires a brief historical review of biological, chemical, and nuclear warfare.

The History – Biological Warfare

As early as the fifth century bc, Herodotus, a Greek historian, described how Scythian archers of the Black Sea used arrows with tips coated by a substance containing biological material.2 The widespread use of bacteriological agents in an armed conflict can be dated back to 1346, at Kaffa (now Feodossia) where the bodies of Tartar soldiers who died of plague were catapulted over the city walls.3 During the French and Indian War, fought in North America between France and England from 1754 to 1767, Sir Jeffery Amherst, an English General, clandestinely provided the Indians loyal to the French with blankets infected with the smallpox virus. As planned, the resultant epidemic devastated the Indian allies.

The most significant and ambitious known biological warfare program to date was started by Japan in 1937. The Manchurian laboratory complex was code named “Unit 731”.3 The Japanese subjected thousands of allied prisoners of war to experiments with biological agents until 1945. An additional offensive bio- logical warfare program was discovered in Russia. In April of 1979, there was a tremendous blast in the city of Sverdlovsk. Res- idents of the city identified the blast as originating from Military Compound 19. Over the next several weeks, more than 40 peo- ple died of inhalational anthrax. U.S. government intelligence sources maintained that for many years a massive accident had occurred at a biological weapons production facility and released anthrax spores into the atmosphere. U.S. suspicions were con- firmed when President Boris Yeltsin acknowledged at a 1992 press conference that the Sverdlovsk incident was in fact a mas- sive biological weapons accident involving aerosolized anthrax spores.3 In the fall of 2001, two employees from the Brentwood mail facility in Northeast Washington, DC, died after inhaling spores form an anthrax-contaminated letter sent to lawmakers on Capitol Hill.

184 Koenig and Schultz's Disaster Medicine : Comprehensive Principles and Practices, edited by Kristi L. Koenig, and Carl H. Schultz, Cambridge University Press, 2009. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/apus/detail.action?docID=564432. Created from apus on 2018-03-08 07:05:26.

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PE R S O NA L PROT E C T I V E EQ U I P M E N T ■ 185

The History – Chemical Warfare

There is debate as to what culture should be credited with the initial development of chemicals for military use during conflicts. If not the actual originators of chemical warfare, the Chinese were clearly early masters of using chemicals on the battlefield.4 Early Chinese planners, strategists, and military leaders were aware of the tactical value of chemical weapons. Chinese writings detail the early use of riot control agents to suppress peasant revolts and the military delivery systems used by the conquering Chinese army.

An early recorded use of gas warfare dates back to the fifth century bc, during the Peloponnesian War between Athens and Sparta. Spartan forces attacking an Athenian city placed a lighted mixture of wood, pitch, and sulfur under the walls hoping that the noxious smoke would incapacitate the Athenians.5

In 1915, the first chemical war agent was used by the Ger- man military forces during World War I. In Ypes, Belgium, they released approximately 168 metric tons of chlorine gas, killing as many as 5,000 Allied troops.6 The accidental discovery of tabun and sarin by German industrial chemistry scientists during pes- ticide research and testing in 1938 lead to the later widespread reproduction and stockpiling of these agents by the then Nazi regime. 6

The History – Nuclear Warfare

The first fission weapons (atomic bombs) were developed in the United States during World War II in what was called the Man- hattan Project. Two of those initial weapons were subsequently dropped on the cities of Hiroshima and Nagasaki, Japan. Rel- atively soon after the United States use of these weapons, the Soviet Union began their own nuclear weapons program, which lead to the Cold War and the development of more powerful devices (hydrogen bombs). At the height of the Cold War, the Untied States and the Soviet Union possessed enough nuclear weapons to destroy both countries and their allies many times over. The end of the Cold War failed to end the threat of nuclear weapon use, however. Fears have risen that nuclear weapons from cash starved former Soviet Union countries may be pur- chased by international terrorist groups. In modern times there are at least seven countries with functional nuclear weapons and both North Korea and Iran have active nuclear weapons programs.

A different type of radiation risk from that of nuclear weapons is the threat from radiological dispersal devices or “dirty bombs” that combine an explosive, such as dynamite, with radioactive material. According to the U.S. Nuclear Regula- tory Commission, most dirty bombs “would not release enough radiation to kill people or cause severe illness – the conventional explosive itself would be more harmful to individuals than the radioactive material.”7 Such devices, however, have the potential to cause widespread anxiety within the population and produce significant property contamination.

The Threat

According to Lieutenant General Michael D. Maples, the 16th Director of the United States Defense Intelligence Agency, “sev- eral terrorist groups, particularly al-Qaida, remain interested in chemical, biological, radiological and nuclear weapons. Al-

Qaida’s stated intention to conduct an attack exceeding the destruction of 9/11 raises the possibility that future attacks may involve unconventional weapons.”8 In addition, the U.S. National Infrastructure Protection Plan states, “Current analysis of terrorist goals and motivations points to domestic and inter- national Critical Infrastructure and Key Resources (CI/KR) as potential prime targets for terrorists.”9 Terrorist organizations, whether domestic or international, understand the value of tar- geting symbols of stability. Future attacks on economic, trans- portation, healthcare or government infrastructure, and key resources have the potential to result in mass casualties. This can adversely impact the economy and more importantly destroy public confidence, morale, and resolve. The best defense is knowl- edge of the most up-to-date equipment, technology, training, and performance expectations in confronting a disaster situa- tion. This includes PPE.

The Hazards

In responding to disasters, healthcare providers may be exposed to toxic and infectious agents. Therefore, knowledge of PPE and why such equipment would be necessary is important. Matching the right PPE ensemble with the right hazard is essential to a proper response and most importantly, the health and well-being of the responder. One size or ensemble does not fit all hazards, training levels, or abilities.

Training and redundant safety systems can reduce the risk for a hazardous materials incident and the subsequent potential for mass casualties with serious injuries. Despite the relatively low rate of problems as a result of chemical exposures in the U.S. depicted in Table 13.1, there exists the need to educate and train all those who have the potential of becoming contaminated. Table 13.2 details the frequencies of injuries or symptoms by type of event.

The primary reason for providing training, education, and the proper equipment to those responding to victims of chemical, biological, and radiological exposures is to prevent the immediate and long-term health consequences that can result from both primary and secondary exposures.

Exposure

In chemical contamination, a primary exposure results from direct contact with the agent (solid, liquid, or vapor). A sec- ondary exposure results from the evaporation or “off-gassing” of the material from a contaminated source at normal atmospheric pressure. In both cases, symptoms vary depending on the level and duration of exposure. Depending on the hazardous mate- rial, victims can experience respiratory difficulties, abdominal symptoms, painful skin lesions, damage to mucous membranes, and death. Long-term health consequences from exposure to toxic chemicals can result in chronic respiratory damage, chronic conjunctivitis, keratitis, and a predisposition to airway cancers. A relationship between a single exposure to some agents, such as mustard, and airway cancers has not been established.11

To address the special hazards from chemical warfare agents such as sulfur mustard, the U.S. Centers for Disease Control and Prevention (CDC) publishes recommended airborne expo- sure limits to protect the health and safety of workers and the public during treatment, transport, or disposal of these agents. The CDC continually evaluates and updates these guidelines.

Koenig and Schultz's Disaster Medicine : Comprehensive Principles and Practices, edited by Kristi L. Koenig, and Carl H. Schultz, Cambridge University Press, 2009. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/apus/detail.action?docID=564432. Created from apus on 2018-03-08 07:05:26.

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186 ■ PAU L D. KI M, FR A N K J. DE N N Y, A N D SA R A H J. SA L K-PO P E

Table 13.1: Frequency of Chemical Release by Substance Categories in All Events and in Events with Victims∗10

No. of Releases Percentage of Releases Substance Category No. of Releases (%)¶ with Victims (%)¶ with Victims

Acids 665 7.3 95 13.3 14.3

Ammonia 466 5.1 74 10.4 15.9

Bases 369 4.1 28 3.9 7.6

Chlorine 205 2.3 48 6.7 23.4

Formulations 16 0.2 1 0.1 6.3

Heteroorganics 80 0.9 4 0.6 5.0

Hydrocarbons 94 1.0 6 0.8 6.4

Mixture† 4,459 16.1 47 6.6 3.2

Multiple substance category 842 9.3 117 16.4 13.9

Other inorganic substances‡ 1,533 16.9 44 6.2 2.9

Oxyorganics 550 6.1 59 8.3 10.7

Paints and dyes 289 3.2 13 1.8 4.5

Pesticides 407 4.5 31 4.3 7.6

Polychlorinated biphenyls 79 0.9 0 0.0 0.0

Polymers 193 2.1 11 1.5 5.7

Volatile organic compounds 1,256 13.8 54 7.6 4.3

Other§ 569 6.3 82 11.5 14.4

Total 9,072 100.1 714 100.0 7.9

∗ Chemicals in events that involved multiple agents were counted only once in a substance category when all the chemicals were associated with the same category. If events involved multiple substances from different categories, they were counted only once in the multiple substance category.

† Substances from different categories that were mixed or formed from a reaction before the event.

§ All inorganic substances except for acids, bases, ammonia, and chlorine.

‡ Not classified.

¶ Percentages do not total 100% because of rounding. In a total of 9,105 events, 33 were excluded because they were not assigned a substance category. For these 33 events, 32 involved one substance each, and 1 event involved two substances that could not be categorized. Six of the excluded events had victims.

As an example, at the time of this writing, CDC recommends a maximum exposure of 0.003 mg/m3 as a 5-minute ceiling limit for sulfur mustard and a general population limit for this agent of 0.00002 mg/m3 averaged over 12 hours (referred to as a 12-h time-weighted average). These standards will meet carcino- genicity protection levels and keep exposures below thresholds for significant risk.12 Such airborne exposure limits also dictate the type of PPE needed to protect workers in a given hazardous environment.

Most exposures to biological weapons will result in flulike symptoms or pneumonia, with the exception of botulinum con- tact. Other significant biological threats include emerging infec- tious diseases such as severe acute respiratory syndrome and pandemic influenza. Many of the issues encountered by first responders, healthcare providers, and public health officials will be the same regardless of the cause. As a result, the most effective response to any disease emergence will probably be rapid iden- tification that an outbreak has occurred. During a bioterrorism incident, however, rapid isolation of the infectious agent to pre- vent further dissemination may not be possible. The illness may

spread through the population for up to 10 days before an inten- tional release is suspected, so waiting for a definitive diagnosis in many cases is not practical. Therefore, implementing some type of syndromic surveillance would be prudent. The investigation of an illness that may represent terrorist activity must examine the epidemiological characteristics of those presenting with signs of infection. A complete clinical history is invaluable in determin- ing whether the onset of symptoms is the result of an endemic disease or a biological weapon. A more detailed discussion of syndromic surveillance is available in Chapter 11.

Radiation exposure provides a much different set of variables that the healthcare provider must address. The actual energy absorbed by human tissue is the most important factor when determining the extent of damage inflicted. The more radiation to which an individual is exposed, the more damage is sustained and the greater the short- and long-term consequences. The dose amount is dependent on the following factors

■ The number and energy level of the radiation particles emit- ted by the source

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PE R S O NA L PROT E C T I V E EQ U I P M E N T ■ 187

Table 13.2: Frequencies of Injuries or Symptoms by Type of Event∗10

Type of Event

Fixed Facility Transportation All Events

Type of Injury No. of Injuries (%)‡ No. of Injuries (%)‡ No. of Injuries (%)‡

Chemical burns 91 3.4 20 6.5 111 3.7

Dizziness/central nervous system symptoms 302 11.4 11 3.6 313 10.6

Eye irritation 268 10.1 28 9.1 296 10.0

Gastrointestinal symptoms 354 13.3 15 4.9 369 12.4

Headache 381 14.3 27 8.8 408 13.8

Heart problems 10 0.4 1 0.3 11 0.4

Heat stress 11 0.4 0 0.0 11 0.4

Respiratory irritation 825 31.1 78 25.3 903 30.5

Shortness of breath 47 1.8 7 2.3 54 1.8

Skin irritation 162 6.1 13 4.2 175 5.9

Thermal burns 76 2.9 9 2.9 85 2.9

Trauma† 101 3.8 97 31.5 198 6.7

Other 28 1.1 2 0.6 30 1.0

Total 2,656 100.0 308 100.0 2,964 100.1

∗ The number of injuries is greater than the number of victims (1,835) because a victim could have more than one injury.

† Examining the 198 trauma injuries, 39 were chemical related, 134 were not chemical related, 7 were both chemical and nonchemical related, and the type of trauma was missing for 13 injuries.

‡ The injuries of one victim were not reported. Percentages do not total 100% because of rounding.

■ The distance from the source (distance is especially impor- tant with α radiation; if one is more than a few centimeters from the source, the dosage approaches zero)

■ The amount of exposure time ■ The degree to which radiation dissipates in the air or in other

substances between the source and the recipient ■ The penetrating power of the radiation13

The potential long- and short-term health effects of radiation also depend on which organs of the body are most likely to absorb radiation.

■ If ingested, radiation from some sources tends to accumulate in certain organs. For example, iodine-131 concentrates in the thyroid gland, where the β radiation, at high doses, can be effective in destroying hyperactive thyroid cells.

■ Water containing tritium (a radioactive isotope of hydrogen) distributes β-emitting radioactivity throughout the body.14

It is critically important to match the appropriate PPE to the biological, chemical, or radioactive agent to ensure effective barrier protection against potential immediate and long-term hazardous effects.

Considerations for the Use of Personal Protective Equipment

Although the use of PPE is important, one must first under- stand that PPE is not the first choice for protection of workers

or potential victims of exposure to hazardous materials. Protec- tion is broken down into a hierarchy of levels organized in order of descending preference. Engineering controls, such as building ventilation systems, are the first priority and most effective means of protection. The second order of protection is administrative controls. Examples include the U.S. Federal Manager’s/Decision Makers Emergency Guide, in which strategies for protecting vic- tims from exposure are discussed and include evacuation versus sheltering-in-place for a short time.15 PPE is considered the least desirable within the hierarchy because of dependence on the indi- vidual to consistently use the equipment correctly. PPE includes anything used by an individual for protection against an agent, for example, a hat to shield against the sun. PPE design and sophistication becomes more complex as the array of agents becomes more hazardous and multifaceted.

The selection of PPE is challenging and is based on sev- eral factors: 1) the environment in which the hazardous agent is deployed, 2) the concentration of the agent, 3) the type of threat encountered (infectious particle, liquid, vapor, or radiation) and 4) the duration of an individual’s exposure to the hazardous agent. Additionally, the individual who will use the PPE has an impact on the type of equipment. Not all respirator designs can be worn by all individuals. Industrial hygienists, safety professionals, and manufacturers should be consulted when selecting PPE.

In general terms, several organizations have developed guide- lines for ensembles of PPE that are effective under increasingly hazardous conditions and have classified them into levels. This equipment is designed to offer increasing levels of safety for eyes,

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Table 13.3: Decontamination Suit Ensembles Levels A–D

Description Advantages Disadvantages Example

Level A Fully encapsulated suit with self-contained breathing apparatus (SCBA)

The highest level of protection, offers protection against contact and inhaled hazards.

The expense, training, and program maintenance restricts the use of this level to specialized hazardous response teams. The lack of mobility in the ensemble, increased heat/physical stresses, and limited air supply restrict the personnel who can utilize this capability.

Level B Suit with sealed seams, supplied air respirator or SCBA

A high level of protection. Utilized in an unknown environment. This ensemble offers more dexterity and mobility then Level A.

Dependent on an air line or limited air supply. Expense, training, and program maintenance are limiting factors. Heat/physical stresses remain an issue. Fit testing is required. Does not protect in a vapor-IDLH environment.

Level C Splash suit and air-purifying respirator (APR)

Compared with Level A and B suits, mobility is significantly increased; heat/physical stresses are reduced. Operational time in the ensemble is increased with a high level of protection against a limited number of chemical agents. Fit testing is not required if hood is used. Moderate expense and training.

The Level C ensemble is not adequate for exposure to substances at high concentration levels, high risk of significant splash contamination, and low oxygen atmospheric levels.

Level D Work clothes with standard precautions (gloves and splash protection)

Highest mobility, low heat/physical stresses, operational time unlimited. Expenses and training minimal.

No protection against chemical and a variety of other hazardous materials.

skin, and the respiratory system. In the U.S. the Environmental Protection Administration (EPA) and Occupational Safety and Health Administration (OSHA) are the two prominent organiza- tions with significant responsibilities for PPE levels and classifica- tions. EPA and OSHA use levels A through D to organize ensem- bles of PPE (Table 13.3). Level A provides the greatest degree of protection utilizing a totally encapsulating chemical-protective suit, whereas level D provides the least protection, essentially utilizing cloth garments. The level A suit is mandatory in an environment that is immediately dangerous to life and health (IDLH). IDLH refers to the maximum concentration level of a substance from which an individual could escape within 30 minutes of exposure without incapacitation or that would result in irreversible toxic effects. For example, the IDLH limit for hydrogen sulfide is 300 parts per million. Levels B and C pro- vide intermediate protection between levels A and D, shielding the skin, eyes, and respiratory system without encapsulating the wearer. Level B provides maximal eye and respiratory protection, mandating the use of atmosphere-supplying respirators. It is less effective in preventing skin exposure, especially in a concentrated vapor environment. Level C should only be used when both the offending agent and its concentration are known, and an IDLH environment does not exist. Level D, in combination with stan- dard precautions, is sufficient protection when caring for many biological casualties and victims contaminated with radioactive material. When encountering certain biological entities, such as viruses, or very fine radioactive particles, a respirator may be necessary. This situation is controversial, and some experts recommend level C.

When selecting PPE for protection from hazardous materials, particularly ones in which an IDLH situation is suspected, begin

with level A protection and then gradually reduce the level of PPE based on a hazard analysis. The U.S. Department of Homeland Security and other organizations frequently refer to these levels when making recommendations for protection. As an example, the final work product of the Working Group on Radiological Dispersal Device (RDD) Preparedness – Medical Preparedness and Response Sub-Group discusses medical guidelines for radiological protection of first responders and first contact medical personnel. It states, “Level C is generally sufficient for particulates . . . If chemical agents are suspected, level B or higher protection is required.”16

In addition to EPA and OSHA, the U.S. military and the National Fire Protection Association have classified PPE into ensemble levels of protection designed to meet their anticipated needs. When reviewing ensemble levels developed by different organizations, one needs to keep in mind that the elements described with separate terminology all use the same PPE. The only difference is they assemble the equipment into unique com- binations. Therefore, the selection of PPE is still based on the same principle, that defined by the degree of protection the PPE can provide, not on a level or classification. The National Fire Protection Association 1994 organizes PPE into the following classes17

■ Class 1, being the most protective for unknown agents ■ Class 2, designed for instances in which victims are not ambu-

latory and there is probable direct contact with a hazardous agent

■ Class 3, designed for instances in which victims are ambu- latory and direct contact with the hazardous agent is pos- sible

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PE R S O NA L PROT E C T I V E EQ U I P M E N T ■ 189

When deciding which of these ensembles is appropriate, one must keep in mind that these classifications provide for adjust- ments within each level based on hazard assessments. Such vari- ations include the type of gloves and type of air purifying respi- ratory protection selected. Hazard assessments are a significant necessity when selecting assembles and cannot be overlooked or omitted from the process. The U.S. Office of Personnel Manage- ment, when planning for civilian workforce protection, stated in their publication, A Federal Employee’s Emergency Guide, that each agency will “determine the risks faced by its employees, develop a comprehensive strategy, and assess the benefits pro- vided by any protective equipment.”18

In the United States, Homeland Security Presidential Direc- tive 8, National Preparedness, dated December 17, 2003, defines the term first responder as, “those individuals who in the early stages of an incident are responsible for the protection and preser- vation of life, property, evidence, and the environment.” These personnel include, “emergency management, public health, clin- ical care, public works, and other skilled support personnel (such as equipment operators) that provide immediate support services during prevention, response, and recovery operations.” The term first receivers was coined at a later date and applies to individ- uals who did not travel to a site contaminated by hazardous agents but received personnel and equipment from the inci- dent scene. In effect, the disaster site moves as victims and first responders begin arriving at medical care facilities. In theory, there exists more flexibility for determining PPE requirements for first receivers based on the presumption that these individuals would 1) have more information before contaminated personnel and equipment arrived, 2) have less exposure being away from the incident site, and 3) have a more easily controlled environ- ment. Specifically, a lower level of chemical protective clothing and equipment could possibly be used by personnel involved in decontamination at sites distant from the initial exposure.

Early determination of the appropriate level of PPE for healthcare facility first receivers is complicated by the fact that information may be limited in the early period following a haz- ardous materials event. In addition, the communication of data from distant scenes to the hospital can be severely limited. The Tokyo sarin attacks represent the challenges that can occur with communications and lack of a well-rehearsed disaster response system. At 8:35 am on March 20, 1995 the first of the 3,227 victims seeking medical care began arriving at Tokyo hospitals, and it was not until 11:00 am that healthcare facilities received confirmation that the agent responsible for the acute illness was sarin.19

Although the ideal level of PPE for hospital first receivers remains controversial, OSHA’s Best Practices for Hospital-Based First Receivers of Victims from Mass Casualty Incidents Involving the Release of Hazardous Substances addresses this issue. OSHA’s publication made several assumptions in making their recom- mendation for level C. These assumptions include 1) hazardous substances would not be released near hospitals, 2) at least 10 minutes would elapse between the time of exposure and the time that victims would begin arriving at healthcare facilities, permitting off-gassing, and 3) no victim contaminated with a large amount of agent would survive to hospital arrival. If any of these assumptions are not applicable to a given event, the level C recommendation will not apply. In fact, an event occur- ring during the year 2000 in the U.S. state of Georgia demon- strated that an individual heavily contaminated with a toxic agent (industrial strength organophosphate) could survive to hospital arrival. Although neither the patient nor any healthcare provider

Table 13.4: Issues Effecting Selection of the Proper Respirator

Contaminant Factors Workplace Factors

Concentration Environment of Use (confined space, hot, cold, outdoors)

Buoyancy Employee Fitness

Physical State (particle, liquid, vapor, gas)

Activities of the Employee during Respirator Use

Particle Size

Vapor Pressure

Warning Properties (odor, taste, irritation)

Toxicity/Virulence

died as a result of the exposure, one provider required intu- bation.20 Other U.S. government agencies have also addressed the issue of PPE. The Army Center for Health Promotion and Preventive Medicine’s Technical Guide provides PPE recommen- dations to the Army’s military medical treatment facility person- nel handling weapons of mass destruction casualties at their fixed facilities. This publication states, “Level B may be ideal . . . ” and “Level C may be sufficiently protective” based on the use of intuitive judgment. It is clear the solution to this dilemma remains elusive.21

When selecting a respirator, one must consider many con- tributing factors (Table 13.4). Using a respirator in a toxic envi- ronment where conditions may change is challenging. Here, this nonstatic environment can compromise safety when the individ- ual using the equipment must perform tasks that are complex or that change under different conditions. An additionally impor- tant consideration when selecting protective equipment is the population who will be using it. As an example, when the mili- tary selects protective equipment, it assumes a relatively young, physically fit, and compliant workforce. In contrast, the civilian workforce that would normally respond to victims of exposure to a hazardous material consists of individuals with varying body sizes and a wide variety of physical capabilities and fitness. There- fore, the PPE selection process must include all these human variables and characteristics in addition to a complete hazards vulnerability assessment.

There are two types of respirators.22

1) Air-Purifying Respirators – Air-purifying respirators (APRs) use canister or cartridge filters designed to remove specific agents from ambient air. Individuals inhale air through the cartridges, removing the contaminant. These respirators only protect wearers when the filter selected is designed for the specific hazardous agent encountered. An APR fitted with canisters designed to absorb ammonia may not provide ade- quate protection against organic vapors. In addition, the con- centration of the toxic substance must not exceed the filter’s capacity and there must be adequate oxygen in the environ- ment. Surgical masks are not respirators; however, they can be used as PPE for some biological agents and/or infectious agents that do not remain suspended in air. APRs include those that incorporate the filter as part of the mask, use car- tridges or canisters, or use a powered device to move air through the filters. These later devices are known as powered

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190 ■ PAU L D. KI M, FR A N K J. DE N N Y, A N D SA R A H J. SA L K-PO P E

Figure 13.1. APR and PAPR with hood. See color plate.

APRs or PAPRs. Level C protective ensembles frequently use PAPRs to provide filtered air (Figure 13.1).

2) Atmosphere-Supplying Respirators – Atmosphere-supplying respirators provide clean air directly to the user from a source other than the ambient air. The two most common delivery systems use either bottled air carried by individuals typically on their backs (self-contained breathing apparatus [SCBA]) or air supplied by a hose from a fixed source (see Figure 13.2). These respirators are used in level A and B protective ensembles.

The National Institute for Occupational Safety and Health (NIOSH) is another U.S. federal agency that works with OSHA

Figure 13.2. Atmosphere-supplying respirators: SCBA and supplied air shown with level B suits.

to maximize workplace safety. NIOSH has determined that APRs employed in chemical, biological, radiological, and nuclear (CBRN) events should not be used in atmospheres in which haz- ard concentrations exceed IDLH levels or oxygen is deficient (containing <19.5% oxygen). Guidelines established by NIOSH dictate that if healthcare workers encounter an unknown haz- ardous material or high concentrations of known toxic agent (IDLH environment), the user should immediately leave the area. Under these conditions, NIOSH’s respiratory protection guidelines, which are supported by OSHA, dictate that use of the most protective respiratory protection (i.e. level A) is indicated until a determination is made that a lower level of protection can safely protect the user. NIOSH has published detailed user guid- ance for the CBRN APR. In 2004, the Department of Homeland Security adopted the NIOSH criteria for testing and certifying respirators for protection against CBRN exposures. In a scenario in which the agents or their concentration cannot be determined in advance, use of atmosphere-supplying respirators instead of APRs is required.23

There are some CBRN agents that may not cause immedi- ate symptoms in victims when exposure occurs but can result in later impairment.23 Therefore, it is imperative to obtain ade- quate advanced information whenever possible and have the correct respiratory protection available. Postponing respirator selection decisions until the effect of an agent is observed can create additional variables that reduce safety for the user and those in the immediate vicinity. Nevertheless, when individu- als wear assigned PPE for a specific operation or environment, program administrators need to monitor the environment and may need to adjust protection due to changing conditions.24 In the U.S., OSHA regulations specify that civilian employees use only NIOSH-approved respirators.25 A NIOSH-approved res- pirator has a certification number and specific instructions for appropriate use. These instructions are printed on the manufac- turers’ containers as a condition for the safe use of their product; however, OSHA acknowledges that unique situations can arise. Therefore, they state in their respiratory protection standard that they will examine, on a case-by-case basis, situations involving the use of non-NIOSH-tested respirators. An example of such a situation is the use of respirators approved by other federal agen- cies against unique contaminants.26 NIOSH approval is such an

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Figure 13.3. NIOSH-approved N95 respirator. See color plate.

important endorsement that the Defense Logistics Agency in the United States recognizes the need for nonmilitary personnel under their employment to use respirators with NIOSH certifi- cation.27

Bacteria and viruses are particulate elements that can be removed by specifically designed filters.28 Most of these devices are either N95 respirators (Figure 13.3) or designated high- efficiency particulate air (HEPA) filters (Figure 13.4). N95 devices can remove 95% of oil-free particulate aerosols 0.3 µm in diam- eter and HEPA filters can remove at least 99.97% of airborne particles of the same size. Most bacteriological agents can be filtered with an N95 respirator. As the agent becomes smaller, for example some viruses, there are greater demands placed on the filter and HEPA respirators may be more appropriate. Addi- tionally, not all hazardous biological agents require a respirator for protection due to the nature of dispersal, e.g., large droplets. Surgical masks are sufficient in these situations.

Particulate respirators are not likely to reaerosolize biological particles collected by the filter. There is no evidence that biologi- cal particles can become an aerosol hazard again after impacting a respirator filter.29 Conversely, a respirator’s outer surface area may be contaminated and can be a tactile hazard, so effective infection control procedures are mandatory.

Radiological agents can also pose the hazard of internal con- tamination if such particles are inhaled. Based on the particulate size, filtration by surgical mask, N95 respirator, or HEPA filters is usually effective. PPE should start with the most protective level and can be reduced based on an on-site hazard assessment. In

Figure 13.4. NIOSH respirator with HEPA filters. See color plate.

summary, particles act in a manner consistent with their physical nature, which is why particulate filter selection logic can be the same for any type toxic particle.

Repeated use of respirators by employees is allowed when the manufacturer specifies that the respirator is designed for that application. Repeated use of respirators refers to the redonning of a respirator by the same employee without removal from service. In other words, the employee dons, removes, and then redons the same respirator during a single event. This behavior is acceptable as long as the respirator can maintain an airtight seal between the face and mask.

Training is required for those administering a respirator pro- gram, as well as for those who will wear the devices. There are no specific respiratory protection program training require- ments for such an administrator, even for the performance of fit tests. Consequently, OSHA has created regulation 29 CFR 1910.134(c)(3). It states that a program administrator must be “qualified by appropriate training or experience that is com- mensurate with the complexity of the program to administer or oversee the respiratory protection program and conduct the required evaluations of program effectiveness.” Simply stated, those performing fit tests are required to have the necessary training to perform that function and OSHA considers training to be both formal education and performance-based instruc- tion. Details on respiratory protection courses are available from OSHA’s web page.30

A major disadvantage of equipment providing respiratory protection is that it requires an airtight seal against the face to function. An important exception is the PAPR that uses a hood instead of a mask to deliver filtered air. Devices such as an N95 respirator, many PAPRs, and SCBAs must be fit-tested to provide proper protection. Fit testing is required for all respirators that rely on an airtight seal between the mask and face. An annual check of this seal is necessary with either qualitative or quanti- tative methods to determine whether the respirator provides an acceptable fit. This is the primary component of a respiratory surveillance program. The qualitative fit-test procedures rely on a subjective detection (taste, irritation, or smell) by the respirator wearer of a particular test agent. If the respirator fits properly, individuals cannot detect the test substance to which they are exposed. The quantitative fit-test procedures utilize measuring instruments to determine if there is a leak between the face and respirator.

The relative workplace exposure level determines what con- stitutes an acceptable fit and which fit-test procedure is required. Negative-pressure APR users may rely on either a qualitative or a quantitative fit-test procedure for exposure levels less than 10 times the occupational exposure limit. Exposure levels greater than 10 times the occupational exposure limit must use a quan- titative fit-test procedure for these respirators. Fit testing of tight- fitting atmosphere-supplying respirators and tight-fitting PAPRs should be accomplished by performing quantitative or qualita- tive fit testing in the negative-pressure mode.

Beyond consistently using the equipment correctly, the seal or fit of a respirator becomes more important as the toxicity and concentration of the hazardous agent increases. When the fit is compromised, air, like water traveling down hill, will take the path of least resistance. The result is air traveling around the filter and some level of unfiltered contaminated atmosphere being inhaled. Additionally, the use of a tight-fitting respirator can have a negative medical impact on individuals who already have diminished lung capacity. This is one reason OSHA advises that

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a medical assessment be performed before providing a worker with a respirator.31

The need for a functioning seal is emphasized by both the certifying agency (NIOSH) and the products manufacturers. It is evident that during emergency incidents, seals are often not maintained by users who have not undergone extensive training. The only exception to the fit testing of respirators designed to have a facemask seal is when respirator use falls under the vol- untary provisions of the OSHA respiratory protection standards (29 CFR 1910.134). A beard of facial hair of more than 1 day’s growth that comes between the sealing surface of the respirator and the face is considered by OSHA to potentially compromise the respirator fit.31,32 If the employee detects a leak in the respi- rator, the employee must leave the respirator use area, and the employer must replace or repair the respirator before allowing the employee to return to the respirator use area.33 Equipment such as corrective glasses or goggles or other PPE cannot be worn in a manner that interferes with the facemask seal.34

Although PPE is accepted as a necessary tool for the protec- tion of individuals exposed to hazardous agents, implementing the use of PPE is not easy. The number of variables that must be addressed and the potential for problems to arise with the equip- ment dictate the need to proceed with caution when using this method of protection. According to a 2002 U.S. Bureau of Labor Statistics survey, there were 3.3 million employees using respira- tors. Only approximately half of those workers, however, knew why they were wearing the respirator or were taught how to use it properly. Describing the emergency response work following the U.S. terrorist attacks of September 11, 2001 the publication Protecting Emergency Responders states, “One special-operations panelist described his APR as ‘nothing but a cup sitting there under your chin’ collecting dust that he would breathe into his lungs when he put the mask back on.”35

RECOMMENDATIONS FOR FURTHER RESEARCH

The use by hospital personnel of PPE is relatively new. As such, most of the recommendations regarding selection of appropriate equipment are based on consensus. Currently, limited research exists that offers evidence for the best PPE for healthcare work- ers. In addition, most of the equipment available was designed for military or industrial use. While this chapter has described levels A through D PPE, other classification systems exist that may be country specific or applicable to certain sectors, e.g. the U.S. military’s Mission Oriented Protective Posture or MOPP gear. In a hospital setting the ideal equipment that meets per- sonnel requirements should, at a minimum, be lightweight, pro- vide a reduced amount of heat stress, permit maximal dexterity, facilitate verbal communication, and ensure rapid donning. A hospital (or level H) suit that provides all of these important fea- tures and characteristics does not currently exist. Development of a level H suit in the future would significantly improve the care of contaminated victims.36 The military continues research and development on PPE emphasizing many of the characteris- tics required for use by hospital personnel. As a result, efforts to ensure the military technology is available for use in the civilian healthcare sector must be supported.

In recent times, new approaches to respirator design have resulted in the development of improved respiratory protec- tion. Standard facemask-style respiratory devices have a variety of limitations in the healthcare setting, such as field of vision

limitations, claustrophobic reactions, and fit-test requirements. The hood-style mask eliminates many of the limitations asso- ciated with devices that must seal against the face and appears to improve respiratory protection. By combining the hood-style mask with a blower unit, researchers have found improved results in the level of respiratory protection. Ongoing research through a U.S. and Israeli joint venture, known as the Agreement on Cooperative Research and Development Concerning Counter- Terrorism, incorporates the hood-style mask with a blower unit. The result from the combination hood-style blower system has achieved protection factors of 50,000 in preliminary test results.37

Continued research and development is focusing on a design that will enhance the best features of both technologies for chemi- cal/biological protection.

Although research and development to further improve tech- nologies and capabilities is required if healthcare personnel are to protect themselves and the healthcare infrastructure, it is also equally important that all healthcare personnel be trained and educated on the use of PPE and decontamination techniques. Educating and training a select few who will serve on a spe- cialized “Decon Team” may be shortsighted. Planning for any scenario that will create victims in numbers greater than the one or two patients most healthcare facilities are prepared to handle will require participation by a wide range of healthcare personnel. Education and training designed for all personnel is needed.

Additional Background Information

NIOSH Respirator Selection Logic (RSL) 2004 “This RSL is not intended to be used for selection of respi-

rators for protection against infectious agents or for chemical, biological, radiological, or nuclear (CBRN) agents of terrorism. While respirators can provide appropriate protection against these agents, the information necessary to use the selection logic is generally not available for infectious disease or bioterrorism agents (e.g., exposure limits, airborne concentration). Similarly, CBRN terrorism events may involve chemicals that can quickly degrade respirator materials or have extremely low toxic levels that are difficult to measure.”38

29 CFR 1910.134(d)(1)(iii) states, “Where the employer can- not identify or reasonably estimate the employee exposure, the employer shall consider the atmosphere to be IDLH.”

29 CFR 1910.134(d)(2)(ii) states, “Respirators provided only for escape from IDLH atmospheres shall be NIOSH-certified for escape from the atmosphere in which they will be used.”

OSHA’s preamble states, “Although the Department of the Army argued strongly for OSHA recognition of Army authority to test and approve respirators, the Department of the Air Force commented that it uses only NIOSH-certified respirators, and requested no exception (Ex. 54–443A). OSHA will examine on a case-by-case basis those situations involving civilian contractors whose employees wear non-NIOSH tested respirators that they believe protect employees adequately and have been tested and approved by other Federal agencies and/or departments for use against unique contaminants.”39 NIOSH has indicated that some CBRN agents may not present immediate effects from exposure, but can subsequently result in impairment, illness, or death.40

The 0.3-µm diameter used in the certification testing is approximately the most penetrating particle size for particu- late filters. Although it seems contrary to expectation, smaller particles do not penetrate as readily as 0.3-µm particles.40

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NIOSH Guide to Industrial Respiratory Protection, Publi- cation No. 87–116 states, “Respirator selection is very complex and should be performed by an Industrial Hygienist or other professional knowledgeable in respiratory protection devices.”41

OSHA provides guidance concerning the selection of those responsible for respirator use. Inspection Procedures for the Res- piratory Protection Standard (CPL 2–0.120): “Program Admin- istrator: A ‘respiratory protection program administrator’ is required to oversee and evaluate the respirator program. This individual must be suitably trained and have the appropriate accountability and responsibility to manage the full respiratory protection program.”31 Where significant program deficiencies are discovered, compliance officers should discuss questions about the program with the program administrator to deter- mine how familiar the program administration is with respira- tors, the hazards in the workplace, respirator use in the facility, the respirator standard, and the company’s respirator program.

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