What are the HSE legal exposure limits for welding fumes?

The Health and Safety Executive (HSE) establishes the thresholds for welding fumes, within the Workplace Exposure Limits (WELs). While there is no specific limit for welding fumes as a whole , there are  limits for specific metallic constituents of welding fumes such as chromium, manganese, zinc, copper and such. Welding fumes are deemed carcinogenic and different constituents have different properties and health impacts.  When it comes to fumes such, as the ones produced during stainless steel welding (which include hexavalent chromium) the recommended exposure limit (WEL) is set at 0.01 mg/m³ for an 8 hour timeframe. Other limits are stated in the HSE document titled EH40 which is freely available from the HSE website.