Metalworking Industry

Metalworking is one of the most dangerous applications for workers so it's regulated a lot. Combustible dusts, such as carbon dioxide and ozone, from dry processing and cutting are extremely hazardous. Here are their PELs:

  • Carbon Dioxide: 5000 ppm or 9000 mg/m³
  • Ozone: 0.05 ppm or 0.2 mg/m³


OSHA also regulates the concentration of various metallic dusts because most are toxic when inhaled and more dangerous than other dusts. Below are some of the metallic dusts and their PELs.

  • Aluminum: 15 mg/m³
  • Beryllium: 0.0002 mg/m³
  • Cadmium: 0.005 mg/m³
  • Cobalt: 0.1 mg/m³
  • Hexavalent chromium: 0.005 mg/m³
  • Lead: 0.05 mg/m³
  • Manganese: 5.0 mg/m³
  • Nickel: 1.0 mg/m³


These hazardous effects of these metallic dusts have also been studied by ACGIH. They recommend a more practical limit after analyzing the literal dangers of that chemical. So, many manufacturers tend to strive to meet their limits to subdue risks as much as possible. Here are their limits (TWAs) for the metallic dusts that I listed above:

  • Aluminum: 1 mg/m³
  • Beryllium: 0.00005 mg/m³
  • Cadmium (compounds): 0.002 mg/m³
    • including Hexavalent chromium
  • Cobalt: 0.02 mg/m³
  • Lead: 0.05 mg/m³
  • Manganese
    • Elemental: 0.02 mg/m³
    • Inorganic compounds: 0.1 mg/m³
  • Nickel:
    • Soluble inorganic compounds: 0.1 mg/m³
    • Insoluble inorganic compounds: 0.2 mg/m³


The fluids used in metalworking can also release airborne hazards. So, the National Institute for Occupational Safety and Health (NIOSH) has set out a limit for general metalworking fluids that are airborne. Below is one of these substances and its PEL. 

  • MWF aerosols: 0.4 mg/m³


To view more regulations and recommendations for this industry, visit the following websites.

OSHA - Occupational Safety and Health Administration of the U.S. Department of Labor

ACGIH - American Conference of Governmental Industrial Hygienists

NIOSH - National Institute for Occupational Safety and Health

NFPA - National Fire Protection Association

EPA - United States Environmental Protection Agency

CSB - U.S. Chemical Safety and Hazard Investigation Board


Please note, this is a list of common applicable regulations, not a comprehensive list of all regulations applicable to this industry and may not reflect the latest publications.