The use of PPE is as important as decontamination itself. PPE is mainly used in the receiving and decontamination areas in hospital settings. Many reports in the literature have asserted that the use of level C protective equipment (ambient air is adsorbed and filtered using an absorbent cartridge to protect the respiratory tract) is adequate for medical facilities [6, 11, 12]. However, use of level C equipment is pointless if the causative agent is a gas that is not absorbed by the cartridge; for instance, such devices may not be able to filter out carbon monoxide, or they may not be capable of the heavy metal doping of activated charcoal required to remove cyanides. Consequently, some investigators have expressed concern about the safety of using level C protective equipment, noting that the chemical weapons used by terrorists are not limited to known agents .
Therefore, there is currently no global consensus regarding the level of PPE that should be used at medical facilities [12–14]. Conversely, the filter cartridges that are used for civilian PPE applications were developed by the military to filter out all known agents of chemical warfare and major civil toxic hazards. In fact, military forces all over the world use level C protection; this is because the balloon-like level A suits with their air cylinders represent potential targets on the battlefield. Similarly, the US Occupational Safety and Health Administration recommends use of a powered air-purifying respirator (a form of level C PPE) in hospital settings.
Given that an attack on a society's weak points is by definition an act of terrorism, it is important to focus on those areas and develop worst case scenarios accordingly. Consequently, level C PPE is likely to be sufficient for most hospital settings (receiving and decontamination areas). However, if health care workers responding to an incident exhibit symptoms, then level B protective equipment, which provides a higher level of protection, should be used until the source of the contamination can be identified. Level B equipment either has an air cylinder or it has an air hose that enables fresh air to be obtained from an air supply. It is recommended that medical facilities use the air line type PPE, to which air is supplied through a hose, because the use and maintenance of air cylinder PPE requires training. Furthermore, nearly all medical facilities are already equipped with lines for compressed air, making it practical to use air line type PPE in hospitals.
There are two types of air line type PPE. In one type compressed air is blown continuously into the hood, whereas in the other compressed air is delivered by a mask with a regulator that supplies air on demand. Although the former type permits easier breathing and is safe, it consumes 140 l/min compressed air, placing a burden on the compressed air lines in the hospital. An excessive burden on the compressed air lines could adversely affect mechanical ventilators and other devices that also use the lines. The pressure demand type level B PPE is somewhat more expensive than the continuous supply air line type, and requires the user to be trained to fit the mask. However, it only consumes 40 l/min air and imposes lesser burden on the compressed air system as a whole.
Depending on the circumstances of the facility, either of these level B PPE types should be obtained and prepared for use. Notwithstanding, it is important to remember that level B PPE carries inherent dangers for the wearer. One potential disadvantage is that the time taken to put on the equipment can be considerable, and the system may become contaminated before staff are protected. Some hospitals have introduced level B PPE in Japan.
Secondary poisoning of medical personnel by a toxic gas was recently reported in Japan when toxic agents reacted with gastric acid during a gastric lavage procedure conducted in a patient who had ingested a toxic substance [15, 16]. The episode raised awareness of the necessity for PPE, and closed gastric lavage kits are now commonly employed in Japan when gastric lavage is performed. When sodium azide, cyanides, sulfides and arsenious acid react with gastric acid, hydrogen azide, hydrogen cyanide, hydrogen sulfide and arsine, respectively, are produced. (Of these compounds, hydrogen azide, for example, cannot be absorbed by absorbent cartridges and is thus used to produce chemical weapons.) Although the term 'chemical terrorism' currently implies terrorism involving chemical weapons, it also has become necessary to guard against chemical terrorism involving the intentional contamination of food and drink with lethal chemical substances. For the terrorist, such methods are easier to execute than other means of disseminating a chemical agent. This underscores the need for precautions against secondary exposure during gastric lavage.