The problem of secondary contamination following chemical agent release

In the present issue of Critical Care, an article by Okumura and colleagues has been published on the problem of secondary contamination following chemical agent release [1]. The authors' draw on first-hand experience [2–5] of the secondary contamination experienced during the Tokyo sarin release in 1995. This experience is important, both for the care of contaminated patients and for the safety of medical staff. The Tokyo terrorist attack in 1995 involved the release of the nerve agent sarin, which produced nearly 1500 casualties but only 12 fatalities. The low number of fatalities may have been due to the impure nature of the sarin used, but these figures underline the fact that chemical agent release does not necessarily produce the mass fatalities suggested by the term 'weapons of mass destruction'. The large number of casualties from the terrorist attack and the analysis of secondary contamination casualties from the transmission of sarin gas formed a significant proportion of the injured in Japan. Of the responding fire workers (who are professionally familiar with the management of released hazardous materials) 9.9% suffered secondary contamination, while the rate among medical personnel at St Luke's hospital (where most of the casualties were received) was 23%. The authors note that the rate of secondary exposure by occupation was 39.3% among nurse assistants, was 26.5% among nurses, was 25.5% among volunteers, was 21.8% among doctors, and was 18.2% among clerks, indicating that the degree of secondary contamination rose in proportion to the length of time a medical worker may have spent in contact with an undecontaminated patient. The data presented by the authors underline the need for awareness, particularly among medical responders, of personal protection (cross-contamination?) and methods of decontamination. Monitoring of secondary contamination and the level of protection required by medical staff are a matter of continuing debate. The authors express concern about the use of level C protection (comprising a lightweight agent-proof suit and a filtration respirator) and recommend that level B protection (a heavier suit with a self-contained air supply) should be used by medical responders. Readers should be aware that this view is not generally accepted in the international medical community where level C protection is regarded as being the standard for healthcare workers involved in toxic releases [6,7], allowing them to provide essential emergency medical care inside a contaminated area. Level B protection has inherent dangers for the wearer and these should be …