|Occupational Health and Safety
Hazardous Substances: Lead Poisoning
Ill Health Effects
Lead causes ill-health effects as a result of inhalation, ingestion and through the skin. Lead intoxication is a result of steady buildup
of the metal in the human system.
The signs and symptoms of lead poisoning are extremely variable, the most common being headache, lassitude, abdominal cramps,
gastrointestinal symptoms, muscular aches and pains, poor memory, restlessness, irritability, tremors, convulsions, vomiting,
drowsiness and stupor. More serious symptoms are muscular weakness and those resulting from central nervous system
involvement, which fortunately are extremely rare in industry. Central nervous system involvement may cause convulsions, coma
and eventual death.
Lead primarily affects the blood-forming system so that an anaemia results. Precisely how lead affects the nervous system, the
gastrointestinal system and musculo-skeletal system is not entirely known. Lead is deposited in bones and muscular tissue without
causing any direct disability. Lead is excreted via the kidneys and may eventually damage them. It may also damage blood vessels
and in combination with the kidney damage, may result in hypertension which in turn may result in cardiac and cerebral problems.
Lead colic may be mistakenly diagnosed as appendicitis, and vice versa, which can result in an unnecessary operation, or no
operation when one should be done.
A complete recovery is expected from minor cases of lead poisoning. If the central nervous system of kidneys have been damaged,
permanent disability may result. Lead which has been stored in the skeletal tissues may be released many years after exposure
has ceased when the body becomes excessively acidic (due to illness, for example) and symptoms of lead poisoning may then occur.
Other effects of lead can be damage to male and female reproductive organs and various defects to children of parents who have
been exposed to lead.
Levels of lead in the workplace can be checked either through air monitoring or biological monitoring (measuring levels of lead in the
blood and urine). Lead is absorbed through the lungs, stomach and intestines, and the skin.
Levels of lead in the air can be measured by air contaminant measuring devices. The B.C. WCB standard - 150 micrograms of lead
per cubic meter - is three times higher than the U.S. Standard. We have repeatedly lobbied the WCB to reduce the standard 50
micrograms/m3 which is the Manitoba standard.
Monitoring the quantities of lead in the air is a far preferable method than biological monitoring since there is less danger of over-
exposure to the workers if machines monitor the lea. The U.S. Department of Labor had this to say about air monitoring versus
"While it is true that air monitoring does not always reflect the worker’s total intake of lead, and that biological monitoring may more
accurately indicate the likelihood of adverse physical effects, air monitoring is nevertheless required by the proposed standard for several
reasons. First, air monitoring does reflect occupational exposure to lead. Moreover, we conclude that it would be inappropriate to monitor
employee exposure solely through biological monitoring. We believe it would be contrary to prudent industrial hygiene principles
for the employees themselves to serve as monitoring devices when sophisticated instruments are available to detect
hazardous concentrations of lead in air, often before employees are overexposed. To purposely allow, in even a few cases,
absorption of high levels of lead by employees before corrective action is taken is inconsistent with the goal of preventing
occupational illness". (emphasis added)
Dust and Fume Removal:
Local exhaust ventilation (located where the lead is produced to remove lead dust or fumes before they reach the breathing space
of the workers is the most important method of preventing lead poisoning. Ventilation systems must be properly maintained if they
are to be effective.
Wetting the lead dust with water or vacuuming it with a cleaner fitted with a high efficiency filter is necessary so that dust is not
released into the atmosphere. Sweeping up dust is not acceptable as this causes dust to rise into the general atmosphere and
become inhaled by all workers in the area. Enclosing the lead-producing operation in a separate section of the building will expose a
smaller number of workers.
Coveralls should be worn by workers and should not be removed from the workplace. They must be laundered at least every three
days and more frequently if necessary. Clothes with lead in them should never be blown off with an air hose since the dust rises to
be inhaled by workers.
Dust and fume respirators should be available for use in temporary situations but should not be used as an excuse to avoid
implementing engineering controls.
Lunchrooms, Locker-rooms, Washrooms:
Adequate washing, showering, and changing facilities must be provided so that workers can wash thoroughly before lunch and
coffee breaks and shower at the end of their shift. Separate lockers in separate rooms must be provided for work clothes and street
clothes. Time must be allowed for showering and changing clothes at the end of each shift.
A lunchroom completely separated from the work area must be provided for the storage and eating of food. It must be located close
to the working and changing room so that workers do not have to pass through the shop floor area to get from one to the other.
Most of the above prevention measures are stipulated by law.
New workers must have the prevention procedures explained to them so they understand why such procedures must be followed
so they won’t take short-cuts that would be injurious to their health.
So that new workers would be fully aware of the hazards of lead, we suggested that the BC WCB translate their lead information
booklet into other languages for workers whose first language is not English. The WCB agreed and these booklets are now
available in Italian, Portuguese, Punjabi and Tagalog (Filipino). Please let us know if you would like copies of these booklets or
would like them translated into other languages.
ACGIH TLV 0.05 mg/m3
OSHA 0.05 mg/m3
Source: CAW Health, Safety & Environment Department