What is Lead?
Lead is a cumulative and persistent toxic substance that poses serious health risks to humans and animals. Naturally occurring in small amounts in the earth’s crust, lead has historically been used in various applications due to its unique properties. However, prolonged or excessive exposure can be harmful.
Characteristics of Lead
- Chemical Element: Lead (Pb) is a heavy metal at room temperature and pressure.
- Compounds Covered by OSHA Standards: The term “lead” in this standard includes elemental lead, all inorganic lead compounds, and a class of organic lead compounds called lead soaps. The standard does not cover other organic lead compounds.
- Uses:
- Primary Use: Automotive lead-acid storage batteries (rechargeable batteries using nearly pure lead alloy).
- Other Applications: Lead alloys are also found in ammunition, pipes, cable sheathing, building materials, solder, radiation shielding, collapsible tubes, and fishing weights.
- Historical Use: Lead was widely used as a corrosion inhibitor and pigment in paints. Due to its toxicity, the Consumer Product Safety Commission (CPSC) banned its use in residential and public building paints in 1977.
Regulatory Limits for Workplace Exposure
- Permissible Exposure Limit (PEL): 50 micrograms of lead per cubic meter of air (50 µg/m³), averaged over an 8-hour workday.
- Action Level (AL): 30 micrograms of lead per cubic meter of air (30 µg/m³), time-weighted over an 8-hour workday.
- Reaching the action level triggers several OSHA requirements, including exposure monitoring, medical surveillance, and employee training.