This article originally appeared on Live in the Now.
The U.S. Department of Health and Human Services (HHS) recently released its 13th Report on Carcinogens (RoC), in which it has classified four new carcinogens. This science-based, public health document is congressionally mandated, and identifies a number of potentially dangerous agents, substances, mixtures and exposure circumstances of known or reasonable risk.
What Exactly Are Carcinogens?
Carcinogens include a variety of different items that either are known to, or may reasonably be anticipated to, cause cancer in humans. Types of carcinogens range greatly, and can include chemical, biological and physical agents. While these substances do not cause cancer under all situations or in all cases, they remain potentially dangerous. Numerous factors, including the amount and duration of exposure, as well as individual susceptibility, all play a role in whether or not a person ultimately develops cancer. Many carcinogens are man-made products used in a variety of products, and the four new carcinogens identified all fall under this loose classification.
1-Bromopropane is a synthetic chemical used as both a cleaning solvent and in spray adhesives, and is often used in dry cleaning. The chemical presents as a colorless to pale yellow liquid, and is also used to clean electronics, optics and metals, in addition to its use as an aerosol-applied adhesive. Workers in occupations which involve 1-bromopropane are at a greater risk than the general population. Our understanding of 1-bromopropane’s impact on humans is still developing, but inhalation of the chemical has been found to cause tumors in rodents.
Another chemical that is “reasonably anticipated to be a human carcinogen” is cumene, which is used in the production of phenol and acetone (commonly used for the removal of nail polish), and found in some fuel products and tobacco smoke. Although it is a natural component in coal tar and petroleum, and tobacco smoke is a legitimate source of exposure, the primary risk of exposure exists in an environment or workplace that utilizes cumene. Studies to better understand its impact on humans are needed, but inhalation exposure has been noted to cause lung and liver tumors in mice.
Pentachlorophenol is yet another probable human carcinogen that is used as a wood preservative in the treatment of utility poles, fence posts, lumber and other wood products. This chemical has been regulated in the U.S. since the 1980s as a restricted-use pesticide, but is still used industrially. Again, exposure most commonly occurs in the workplace through the inhalation of contaminated air or dust, or through contact with contaminated soil. Aside from causing tumors in the liver and other organs in mice, pentachlorophenol has also been associated with an increased risk of developing non-Hodgkin lymphoma in human studies.
Of these four substances, ortho-toluidine has the sole distinction of being classified as a “known human carcinogen,” whereas the aforementioned three substances are designated as “reasonably anticipated to be a human carcinogen” according to HHS. Ortho-toluidine is commonly used to make rubber chemicals, pesticides, hair dyes and certain medical and consumer products, and has also been found in tobacco smoke. This synthetic chemical is produced in other countries and imported to the U.S., where people are often exposed through their workplace. While ortho-toluidine has been listed on the RoC since 1983, recent evidence showing that it causes urinary bladder cancer has led to it being reclassified as a known human carcinogen.