Much like its classification of the UV rays from sunshine and “moonshine” (alcoholic beverages), the International Association for Research on Cancer (IARC) has now classified outdoor air as a human carcinogen.

In what may be its most sweeping classification to date, last month IARC announced that outdoor air is the most widespread “human carcinogen.”

The IARC, part of the World Health Organization, classifies potentially hazardous agents by its “Monographs of the Evaluation of Carcinogenic Risks to Humans” as follows:

  • Group 1: Carcinogenic to humans
  • Group 2A: Probably carcinogenic to humans
  • Group 2B: Possibly carcinogenic to humans
  • Group 3: Not classifiable as to its carcinogenicity to humans
  • Group 4: Probably not carcinogenic to humans

Basing their findings on an independent review of more than 1000 scientific papers from studies on five continents, IARC concluded that there is sufficient evidence that exposure to outdoor air pollution causes lung cancer.  The IARC’S evaluation showed an increasing risk of lung cancer with increasing levels of exposure to air pollution.  Although the composition of air pollution and levels of exposure can obviously vary dramatically from place to place, these findings apply to all areas of the world.

In toxic exposure litigation, Plaintiffs with cancer routinely attempt to point to IARC classifications similar to this one, as well as other agency classifications, in an attempt to prove the element of causation.  Yet many courts have held that such classifications are not probative of whether any particular substance caused a plaintiff’s specific disease.  See, e.g., Burleson v. Texas Dept. of Crim. Justice, 393 F.3d 577, 589 (5th Cir. 2004) (“the mere fact that thorium dioxide has been classified by certain regulatory organizations as a carcinogen is not probative on whether Burleson’s exposure to thoriated tungsten electrodes caused his lung and throat cancer”); Allen v. Penn. Eng’r Corp., 102 F.3d 194, 196 (5th Cir. 1996) (“the fact that EtO has been classified as a carcinogen by agencies responsible for public health regulations is not probative of the question whether Allen’s brain cancer was caused by EtO exposure”).

Will the IARC’s new finding regarding air pollution as a human carcinogen lead to an influx of lawsuits against manufacturers alleged to have caused cancer in plaintiffs by polluting the air?  If this occurs, defense attorneys for manufacturing defendants should continue to fight the introduction of such evidence in any toxic exposure case using pre-trial motions to exclude such classifications.  Whether it’s the rays we soak up, the drinks we indulge in, the air we breathe, or something else, the IARC’s classifications are simply not probative of whether any particular exposure caused a plaintiff’s specific disease.

The litigators of Husch Blackwell’s Technology, Manufacturing, and Transportation unit focus on successfully defending a wide range of toxic exposure cases.  We have experience defending manufacturers in cases involving asbestos, lead, polychlorinated biphenyls, benzene, mercury, radiation, and other exposures.

For additional information, please contact Joe Orlet.