Toxic Exposures

9. Chemical Exposures

Matching a constellation of signs and symptoms with an associated syndrome can assist in the identification of the specific chemical exposure. Disaster scene responders should have proper resources available for chemical identification. If a Poison Control Center can be contacted, its personnel will be able to aid in exposure identification and subsequent treatment. Otherwise, provisions for other informational support will be required. For example, in the United States, other sources such as Chemtrec (a HAZMAT communication center) can be ­contacted 24 hours per day by telephone or Internet. The Internet is an extremely valuable tool in times of uncertainty (see “Suggested Reading” for additional website resources). Refer to the Appendix “Chemical Glossary” for further details regarding
specific chemicals and their treatments. As an example, a relatively common chemical exposure is discussed below.

Clinical Presentation of Chlorine Gas Intoxication

Chlorine gas is a strong irritant and may be corrosive to mucous membranes and eyes in concentrated amounts as occurs in industrial exposures. The severity of the exposure depends on different variables, including the concentration of the gas and the duration of the exposure. Despite the general belief, remember that the strength of the odor of the product is not a good indicator of the severity of the exposure. Table 5 shows the expected toxic effects according to the level of chlorine gas exposure.

In chlorine gas exposure the presence of pre-existing cardiopulmonary disease and the water content of the involved tissues are specific factors that determine the severity of the exposure. In serious exposures, severe pulmonary irritation, pulmonary edema, and death may present quite rapidly. Survivors of severe exposures may develop residual pulmonary dysfunction, such as reactive airway disease and low residual volumes. Corrosion is not likely with the concentrations liberated in accidental home production when mixing bleach with an acid-containing cleaner (e.g., usually <1 parts per million [ppm]). A level of 1 ppm, however, is often used as a 15-minute short-term exposure level (STEL) for chlorine for occupational health purposes. Minor exposures usually result in mild burning sensation in the chest, coughing, lacrimation, and tachycardia. Minor exposures in the home may require no treatment other than removal from the exposure with resolution of the symptoms occurring within 1 to 6 hours. Those patients with persistent symptoms or chronic lung problems may require further evaluation and treatment. In some patients, symptoms may be delayed for up to several hours after exposure to chlorine gas. See Appendix for more information regarding the timing of onset of signs and symptoms for different toxic exposures.