Chemical–biological–radiological (CBR) response: a template for hospital emergency departments

To the Editor: Tan and Fitzgerald's template for emergency department response to chemical–biological–radiological hazards appears to be based on a dubious assumption of a low level of risk.1 A recent report details exposure of emergency department staff to potentially fatal secondary contamination during a hazardous materials incident, highlighting the need for staff to have the appropriate training and equipment to deal with these events.2

I believe the level of Personal Protective Equipment (PPE) proposed by Tan and Fitzgerald is inadequate. The "facemask with filter" they describe is classified as Level C respiratory protection, and this level only conforms to the Australian Standard (for PPE) when the identity of the chemical and its vapour concentration are known, and when these do not exceed the filtering capacity of the particular filter mask being used.3,4 In the initial confusion of a hazardous materials incident, the identity of the chemical agent and its vapour will not be known. There may even be misinformation: during the 1995 Tokyo sarin attack, for example, initial advice to hospitals by the Tokyo fire service was that the incident was "a gas explosion in the Tokyo subway".5

Emergency department staff must be able to respond before the nature and severity of the chemical hazard can be determined. The only respiratory protection which conforms with the Australian Standard for PPE when the nature and severity of the chemical hazard has not been determined is the supplied gas respirator with full face shield of Level A (an encapsulating suit and self-contained breathing apparatus) or Level B (a non-encapsulating suit with self-contained breathing apparatus or a full face respirator on a gas line).3,4

Confronted with a hazardous materials emergency, potentially involving very toxic chemicals, emergency department staff need to have complete confidence in their own protection. This is only possible with the use of supplied gas respirators (Level A or B PPE), which provide complete respiratory protection. An additional problem with Level C air-purifying respirators is that their performance may be adversely affected by water ingress into the filter, which could occur during the decontamination procedures described in the template.

Tan and Fitzgerald also propose having a clerk don PPE and enter the contaminated zone. Any stationery taken into a contaminated area would have to be decontaminated before being taken out to a "clean" area, and it is not clear what a clerk would add to the initial response within a contaminated zone.