10.3 Lead

Lead compounds are used in construction in paint primers on steel and iron, in alloys, in lead shielding in walls and in lead pipes. In the body, lead circulates in the blood and builds up in organs, causing harm to tissue that cannot be reversed. The body removes most of what it absorbs, but some stays in blood and tissue, and with continued exposure the amount stored grows until it becomes lead poisoning, which can be fatal.

Routes of exposure

• Inhalation is the most common route, from lead particles in the air.
• Ingestion occurs when a worker smokes in a contaminated area, carries lead from hands to a cigarette and then to the mouth, or eats or drinks contaminated food and drink. Workers who do not follow hygiene rules can carry lead home and harm their families.

Activities that cause exposure

Removing lead paint, melting and casting lead and babbitt metal, torch soldering, reclaiming lead acid batteries, grinding or sanding lead materials, machining lead, and cutting lead material with a torch.

Health effects

Lead can damage the nervous, urinary, blood forming and reproductive systems. It causes anaemia by hindering the formation of haemoglobin, can damage kidney cells and lead to kidney failure, and reduces sperm count and fertility in men. A pregnant woman's lead can cross the placenta to the baby.

Early signs are easily mistaken for everyday complaints: loss of appetite, a metallic taste, irritability, aches in joints and muscles and poor concentration. Later signs are anaemia, kidney failure, stomach pain, convulsions, and wrist or foot drop.

A worker who is exposed at or above the action level for more than 30 days a year receives initial medical surveillance. The employer must provide medical monitoring at regular intervals, and further examinations when blood lead levels are high.

Engineering controls

• Exhaust ventilation. Equipment that removes lead paint must have a HEPA filtered vacuum attached to collect the dust. Provide local exhaust ventilation for welding, cutting, burning and heating, and clean up only with HEPA vacuums so that lead does not get into the air.
• Encapsulation. Make lead paint inaccessible by covering it with epoxy, acrylic or flexible wall covering, or enclose it behind plywood panelling, gypsum board, aluminium or vinyl. Cover floors with vinyl tile or linoleum.
• Substitution. Use epoxy covered zinc primers in place of lead coatings, a mobile hydraulic shear instead of a torch to cut lead material, surface preparation equipment in place of abrasive blasting, and chemical strippers in place of scraping or a heat gun.
• Process change. Apply lead paint with brushes or rollers instead of spraying. Use hydro blasting or vacuum blasting instead of dry abrasive blasting.
• Isolation. Where blasting cannot be fully enclosed and ventilated, isolate it and restrict entry with warning signs.

Personal protection and hygiene

• Use changing areas, showers and washing facilities properly.
• Never eat, drink or smoke in or near lead work areas.
• At the end of the shift, put disposable clothing and shoe covers in sealed, impermeable bags for lead waste. Place contaminated clothes, shoes and PPE in a closed container for professional laundering. Shower and wash hair, then put on street clothes.
• The employer provides clean, dry protective clothing and equipment, including respirators, free of cost, informs in writing anyone who handles contaminated clothing of the hazards, trains workers and keeps records of exposure assessments.

A study aid, not published or endorsed by IOSH or OSHA. Laws and limits differ between countries.