Welding & Hexavalent Chromium
The chromium found in stainless steel is converted to its hexavalent state during the welding process, and these highly toxic fumes can pose some serious health consequences, not the least of which being lung and larynx cancer.
Let’s bear in mind as well that a single welder can produce 20 – 40 g of fumes per hour, or upwards of 70 kg a year. That is a lot of weld smoke that may contain some pretty nasty elements, and some of these particles are fine enough to penetrate deep into the lungs (anything from 0.1-5 µm)
There are OSHA regulations pertaining to hexavalent chromium. The permissible exposure limit, for example, is 5µg/m3 as an 8-hour time-weighted average. I don’t quite understand how a welder is supposed to monitor these things to make sure he or she isn’t exceeded these permissible limits. Naturally, it is incumbent on management and health-and-safety professionals at each facility to take the appropriate measures to ensure that their team members aren’t being subjected to exposure beyond these limits.
If you want to read-up on the OSHA regulations as it pertains to hexavalent chromium – Cr(VI) – check out 29 CFR 1910.1026 and 1926.1126.
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1026
https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.1126
For welders, to protect yourself you should insist on some form of ventilation to remove gases from your breathing zone. Any at-the-source solutions should be given top priority. You should also avoid welding in confined spaces without the aid of proper ventilation.
I’ve always sympathized with office staff who must occasionally walk out onto plant floors in facilities that do not employ a form of fume extraction. Even though their exposure may be limited, they’re nonetheless being exposed to a nasty group of compounds. I was in a shop recently with a health-and-safety professional witnessing plumes of weld smoke envelope a welder, before drifting to the ceiling. The welder was wearing a respirator, but we certainly weren’t. When I inquired about them employing a form of weld fume extraction, the person I was with literally walked up to the welder and asked if he thought it was necessary. When he answered he didn’t she simply parroted what he said. It begged the question – aren’t you the person best suited to make that determination?