Foundry Industry

In the various production operations within the foundry/metallurgical industry, several different chemicals and dusts pose hazards. When processing the metal from ore, large emissions of sulfur oxides and particulates are present. When producing alloys, the major air contaminant is particulate in the forms of metallic fumes, smoke and dust.

The most threatening airborne particles are respirable dust, silica, and silicon. Here are their PELs:

  • Nuisance Dust
    • Respirable Fraction: 5 mg/m³
    • Total Dust: 15 mg/m³
  • Silica
    • Quartz (respirable): 10 / (% SiO₂ + 2)
    • Quartz (total dust): 30 / (% SiO₂ + 2)
    • Cristobalite: ½ the value calculated for quartz
    • Tridymite: ½ the value calculated for quartz
    • OSHA Proposed limit for Respirable Crystalline Silica: 50 µg/m³
  • Silicon
    • Respirable Fraction: 5 mg/m³
    • Total: 15 mg/m³


There are many other metallic fumes and dusts associated with foundry work that also pose significant hazards. Below are PELs for some of these substances. 

  • Acrolein: 0.25 mg/m³
  • Benzene: 10 ppm
  • Cadmium Fume: 0.1 mg/m³
  • Cadmium Dust: 0.2 mg/m³
  • Chromium compounds: 0.5 mg/m³
  • Copper Fume: 0.1 mg/m³
  • Iron Oxide Fume: 10 mg/m³
  • Magnesium Oxide Fume: 15 mg/m³
  • Manganese Fume: 5 mg/m³
  • Oil Mist: 5 mg/m³
  • Phenol: 19 mg/m³
  • Styrene: 100 ppm
  • Sulfur Dioxide: 13 mg/m³
  • Toluene: 200 ppm
  • Tellurium and compounds: 0.1 mg/m³


Other organizations recommend limits for thoracic fractions as they contain the same hazards as respirable fractions. 

The National Institute for Occupational Safety and Health (NIOSH) recommends an exposure limit for:

  • Total thoracic particulate mass: 0.5 mg/m³

The OSHA Metalworking Fluids Standards Advisory Committee, based on studies of diminished lung function, recommended a limit of:

  • Thoracic particulate: 0.5 mg/m³


It is pertinent that you are aware of and utilizing these exposure limits to protect your employees and avoid costly citations like this steel foundry faced.


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.