Antioxidant Administration Reduces Lung Injury from Chlorine Exposure

Edward Postlethwait, Ph.D. and Sadis Matalon, Ph.D.
Department of Environmental Health Sciences, University of Alabama at Birmingham
NIEHS Grant U01ES015676

Dosages of vitamin C and other low molecular weight antioxidants may help prevent chlorine-induced lung injury that occurs after railroad tanker spills or might occur as a result of terrorist attacks according to NIEHS-supported research from the University of Alabama Birmingham. The levels of chlorine exposure used in the research study mimic those seen during accidental exposures.

Chlorine is a powerful oxidant that is used in bleaches, disinfectants, and in a wide variety of industrial processes. Under normal conditions, it is a pale green gas that is denser than air. Thousands of tons of chlorine gas are transported by rail in the US each year. Recently chlorine rail cars have been suggested as targets for terrorist attacks. Media reports suggest that as many as 100,000 people could be killed or seriously harmed from the explosion of a single railroad tank car traveling through a major city.

The research team exposed laboratory rats to chlorine gas at either 184 or 400 parts per million for 30 minutes in controlled environmental chambers. These levels are similar to those measured near chlorine tanker spills. Just one hour after exposure, the rats showed evidence of decrease arterial blood oxygen, increased blood carbon dioxide and acidosis, and increased markers of inflammation in respiratory fluid samples. In a subsequent experiment, administration of a mixture of antioxidants, which included ascorbic acid (vitamin C), deferoxamine, and N-acetyl-L-cysteine, prior to exposure to 184 parts per million chlorine dramatically reduced the respiratory effects seen in the previous experiment.

These experiments suggest that antioxidant administration may be useful for preventing the serious lung injury and death that can occur as a result of chlorine gas exposure. Additional studies will be necessary to confirm these findings, but these results suggest that hazardous materials responders and rescue crews may benefit from prophylactic antioxidant administration prior to responding to a chlorine spill.

Citation: Postlethwait E, Matalon S. Mitigation of chlorine-induced lung injury by low-molecular-weight antioxidants. Am J Physiol Lung Cell Mol Physiol. 2008 Nov;295(5):L733-43.