Is Hexavalent Chromium (Hex Chrome; Chrome VI) Found in Welding Fumes A Carcinogen?

If you need hexavalent chromium (hex chrome; chrome VI) testing/sampling as discussed in this article call us at 1-800-344-4414 or email us at info@atlenv.com for details and a free estimate.

 

Written by Henry P. Shotwell, Ph.D., CIH, Vice-President and Robert E. Sheriff, MS, CIH, CSP, President

November 8, 2018

Neither the chromium found in metal plating (like chrome trim on a can) nor the chrome found in medicines like chromium picolinate is in the hexavalent form and is not carcinogenic. In fact it has a positive value in our system by assisting in regulating blood sugar levels.  The chrome found in the fumes formed by welding stainless steel and released into a welder’s breathing zone is in the hexavalent state and can cause lung cancer if the welder breathes in a high enough dose of Chrome VI often enough.  Welding on metals other than stainless steel may also contain hexavalent chromium but the potential for overexposure is less.  The Occupational Safety and Health Administration (OSHA) has determined that a continuous, 8-hour exposure to hexavalent chromium of 0.005 milligrams per cubic meter of air, or less, is an acceptable exposure level (OSHA Regulation 29 CFR 1910.1026).  This new regulation was instituded in 20016 with all provisions in effect on December 31, 2008.  The PEL for an 8-hr day is 5ug/M3 and the actions level is 2.5ug/M3.

In 1990, the International Agency for Research on Cancer (IARC), an agency of the World Health Organization (WHO), published their findings on chromium and chromium compounds as carcinogens. Chromium may be isolated in any of three volume states: Chrome 0 or metallic chromium; Chrome III called “Chrome 3” or Chrome VI called “Chrome 6,” also called hexavalent chromium. Neither Chrome 0 nor Chrome III has shown the ability to cause cancer. Chrome VI, on the other hand, is a well-known lung carcinogen. (DeFlora, S., “Threshold Mechanisms and Site-Specialty in Chromium (VI) Carcinogens,” Carcinogens, Volume 21, No. 4, pages 533-541, April, 2000, Oxford University Press.) However, according to DeSilva, development of lung cancer “…requires massive exposures, as is only encountered in well-defined occupational settings…”

Methods to contain welding fumes should be instituted if the levels exceed even the action level of 2.5ug/M3.

Portable welding fume extractors work well when placed close enough to the point of operation to capture the “smoke” created by welding, thereby reducing or eliminating the smoke from entering the welder’s breathing zone. Using a respirator to filter out the smoke particles is the last line of defense. A respirator has to be correctly chosen for the anticipated contaminant, but it also has to be correctly fitted to the worker’s face, and tested to be sure there is no leakage around the edges of the respirator that might allow contaminants to bypass the filter system.  OSHA requires that workers be properly trained in the use, cleaning, care, and storage of respirators.

Common activities where hexavalent chromium exists are in welding of stainless steel or chrome plated metals and electroplating of chrome. Printing or painting operations where chromium inks or paints are used, may also be a source of Hex Chrome exposure.

In each of these cases, these activities should be sampled to determine if the exposure levels are safe. If it is a work situation, then compliance with the OSHA Standard for hexavalent chromium (29 CFR 1910.1026) must be addressed.  Monitoring the workers while performing hex chrome exposure tasks is also required to insure that any respirators are the proper ones for the workers and the task performed.  The respirator protection standard is 29 CFR 1910.134.

Our primary service areas for Hexavalent Chromium sampling/testing are: NJ, NY, NYC, PA, CT, DE, (Boston) MA, RI, Wash DC, WI, MD, MI, (Chicago) IL, VA, IN, (Atlanta) GA, AL, NC, SC, TN, (Dallas, Ft Worth) TX, OK, DC, AR, we can service most other areas of the U.S. but with some added travel charges.