OSHA Permissible Exposure Limits for Dust: Grain & Silica

The Occupational Safety and Health Administration establishes Permissible Exposure Levels for different types of dust, including grain, silica and lead. All PELs are measured in eight-hour periods that are time-weighted.

Grain Dust

• Grain dust is a combination of husk particles, cellulose hairs, insect debris, rat hair and other pollutants. OSHA has established a PEL of 10 milligrams per cubic meter of air in an eight-hour period.

Silica Dust

• The PEL for silica dust has changed through the years. It was originally based on a 1970s era formula and revised in 1986 to a limit of 0.1 milligrams per cubic meter of air. The current requirement is .05 milligrams per cubic meter of air in an eight-hour period.

Lead Dust

• Lead dust, like other types of lead exposure, is highly dangerous. As a result, the PEL is 50 micrograms of lead per cubic meter of air in an eight-hour period.