Iodine Summary

Expected Concentrations:

Airborne iodine concentrations typically range from 0.002 ppm to 0.15 ppm in Red P Cooks. The highest concentrations exceed the current ACGIH Ceiling TLV of 0.1 ppm. The walls in many of the suspected "cook" areas have brownish- yellow stains that react with spray starch forming a dark blue color, an indicator for iodine. Current standards for iodine are as follows:





Ceiling 0.1 ppm

Ceiling 0.1 ppm

Ceiling 0.1 ppm

2 ppm

General Health Effects:

Airborne iodine is a heavy halogen vapor considered to be more irritating and corrosive than bromine or chlorine gases. In animal studies, iodine vapor has been found to be intensely irritating to mucous membranes, causing damage in both the upper and lower portions of the respiratory tract. Iodine vapors can be an intense irritant to the eyes, mucous membranes and skin and have a steep effects curve in that concentrations of 0.1 ppm may cause very little effect while levels of 0.5 ppm may cause severe irritation. (1)

Exposed workers have experienced burning eyes, tearing, blepharitis, rhinitis, stomatitis, and pharangitis. Even short exposures have resulted in headache and chest tightness. Iodine is changed to iodide in the lungs and eliminated in the urine. Ingestion of as little as 2 to 3 grams may be fatal and chronic exposures may cause insomnia, conjunctivitis, rhinitis, bronchitis, tremor, tachycardia, diarrhea, and weight loss. All workers exposed to 1.63 ppm reported eye irritation in two minutes. Hypersensitivity to iodine is typically characterized by a skin rash, a symptom that is frequently reported from methamphetamine laboratory investigations. (2,3)

Although there have been no documented cases of over-exposure to iodine vapor in clandestine methamphetamine laboratories reported in the literature, iodine could be a plausible cause of mucous membrane and eye irritation reported at these investigations. Iodine may persist for some time in the walls, carpeting, draperies, and furnishings. in many of these clandestine laboratories. The fact that it is commonly observed on the walls, even after months of no cooking, suggests that it can be very persistent.Iodine persistence in the environment of the "cook", which is often the kitchen of the residence, results in an important potential exposure to the children that are present in the clandestine laboratories as well as children who inadvertently become residents in a building previously used as a methamphetamine laboratory. Children crawling on contaminated carpeting are likely to have exposures to surface concentrations of iodine.

Health Risks to Children: Children may have more adverse health effects from iodine exposure than adults because they have a higher breathing rate and a greater lung surface area per body size than do adults. In addition, their thyroid glands are still growing and may be more easily damaged by high iodine levels since too much iodine may cause an enlarged thyroid gland (goiter). (3)

Fetal Health Effects: Iodine can pass through the placenta and into mothers milk. Too much iodine can cause a infant's thyroid gland to enlarge and effect breathing. Other fetal toxicity to iodine, other than radioactive iodine, has not been reported.

  1. ACGIH. 2003. Documentation of the ACGIH TLV's - Hydrogen Chloride. American Conference of Governmental Hygienists. Cincinnati, OH.
  2. Proctor, N.H. , Hughes, J.P. 1978. Chemical Hazards of the Workplace. J.B. Lippincott Co. Philadelphia, PA 533 pp.
  3. Salocks, C. and Kaley, K.B. Technical Support Document:  Toxicity Clandestine Labs: Methamphetamine. Vol 1. , Number 2. Iodine. Cal/EPA. Office of Environmental Health Hazard Assessment. Sacramento, CA . 2003. 10 pp.

Additional Information:

Technical Support Document: Toxicology Clandestine Drug Labs: Iodine
Office of Environmental Health Hazard Assessment

Toxicology of Iodine
2003 Office of Environmental Health Hazard Assessment