Stainless steel - hexavalent chromium (Public safety announcement)

[Templar1191]

Welding can generate between 2g/kg to 20g/kg of chromium 6+ (source:"Selecting Processes to Minimize Hexavalent Chromium from Stainless Steel Welding") but that weld arc is about the same temperature as the surface of the sun. You just wont see those temperatures on a coil (hope not).
Most of us arent welding stainless steel every day. Are you dry firing your stainless steel coils? Do it outside. Dont inhale the fumes. When you are done dry firing, wash the entire rda setup.

Hexavalent chromium
The US Occupational Safety and Health Administration (OSHA) have set a Permissible Exposure Limit (PEL) of 5 ug/m3 , as an 8 hr time-weighted average (TWA). Source: "A comparison of direct-reading instruments for the measurement of hexavalent chromium during stainless steel welding". An absolute limit of 50 ug/m^3 for 15 minutes is set. If you experienced this concentration of chromium in the air for a couple hours, you may start to feel very sick due to 6+ poisoning. If you did it regularly, you would significantly increase your chances of contracting cancer and lung problems.

Other chromium oxides, eg Cr(III) are used naturally in trace amounts by the body for enzymes, so they arent particularly toxic.

Carry on people, the hexavalent bogey man is a problem for welders, but he doesn't exist here.

 

[Alexander Mundy]

Was well discussed in the past in a very long thread when SS mesh was being used in the genesis days. Lab testing was also done and no CR VI was present. The general consensus was (as you state) that the temps just were not high enough.

 

[Templar1191]

Interesting. Did they dry fire the stainless mesh to glowing? Ss mesh is quite different to coils
I would guess much better heat distribution

The only time any hexavalent would form is during dry firing.