The heavy metal, lead is a commonly used material for a number of industrial processes. Because it’s a neurotoxin that can be hazardous to humans in even small amounts it’s vital that workers, and the public at large, be protected from exposure.

Q. What are the symptoms of lead poisoning?
A. Symptoms of lead poisoning are not always easily recognized. Some symptoms that may occur in adults include: high blood pressure, digestive and nerve disorders, memory and concentration problems, and joint and muscle pain. In children, symptoms are more severe: damage to the brain and nervous system, behavior and learning disabilities, developmental delays, and slow growth.

Cardio-pulmonary-shortness of breath, cough, chest pains, palpitations, or orthopnea.

Gastrointestinal-nausea, vomiting, heartburn, abdominal pain, constipation or diarrhea.

Neurologic-irritability, insomnia, weakness (fatigue), dizziness, loss of memory, confusion, hallucinations, incoordination, ataxia, decreased strength in hands or feet, disturbances in gait, difficulty in climbing stairs, or seizures.

Easy fatigability, abnormal blood loss,.

Reproductive (male and female and spouse where relevant)-history of infertility, impotence, loss of libido, abnormal menstrual periods, history of miscarriages, stillbirths, or children with birth defects.

Musculo-skeletal-muscle and joint pains.
Although the hazards of lead have been known since ancient times, only recently have the hazards been taken seriously. It was not until modern times that preventative measures of limiting exposure were researched and tested. Modern tests, such as urinary and blood level measurements, have led to establishing acceptable air levels, as well as control methods for occupational exposure to lead. A common industry goal of 150µg/m3 (micrograms per cubic meter of air) averaged over an 8-hour time period was accepted in 1933 by the U.S. Public Health Service and remained consistent throughout the 1940s into the 1950s. 150µg/m3 remained the same until 1957 when the American Conference of Governmental Industrial Hygienists (ACGIH) raised the level to 200µg/m3 based on national consensus standards found in the American National Standards Institute (ANSI) Z37.11-1969 (adopted by OSHA and found in table Z-2 of 29 CFR 1910.1000). In 1971, the ACGIH lowered lead exposure levels back to150µg/m3; this due to national consensus standards not based on any type of clear rationale and the ACGIH could not find enough evidence to support the fact that the exposure level was raised in the first place.

The final rule on occupational exposure to lead for the general industry was issued in November 1978. The new standard changed the permissible exposure limit (PEL) for lead from 150µg/m3 to 50 µg/m3 averaged over an 8-hour workday.

Testing for the presence of lead can be done in the following ways:

It is required to test a representative number of employees and job types. The air samples taken must be representative of the each employee’s regular, daily exposure to lead. Enough sampling must be done to make sure that each employee’s exposure level is reasonably represented by at least one full-shift (at least 7 hours) sample.

Lead levels must be rechecked every six months if the exposure level exceeds the action level and every three months if it is exceeds the PEL. Monitoring can stop if the employer has monitored for lead twice, testing at least two weeks apart, with results lower than the action level.

Determination of air concentrations. Two pieces of equipment are needed for this—a personal air sampling pump and a membrane filter. These can be attached to an employee
Determination of water concentration. Obtain a water test kit or submit a sample to an analytical laboratory
Determination of soil concentration. Obtain a soil test kit or submit a sample to an analytical laboratory of your choice.
Determination of blood leads level. Determined by blood sample taken by physician.
NOTE: The exposure level for lead in blood is 50µg/dl (micrograms per deciliter).
Determination of surface lead level. Can be determined by convenient test kits.
NOTE: Once the lead level is determined, it should be compared with the recommended level.

Personal Protective Equipment

The employer is required to provide respiratory protection and protective clothing for those that are exposed to lead levels above the PEL (50µg/m3)

Safe Work Practices

When working with lead, these practices apply

Provide exhaust ventilation.
Use only HEPA (High-Efficiency Particulate Absolute) vacuums for cleanup.
Use a NIOSH/MSHA-approved respirator. (The type will be determined by the exposure level.)
Do NOT eat, drink or smoke in lead-contaminated areas.
Use proper protective clothing, shoe covers and gloves.
Wash hands thoroughly before eating.
Shower and change into clean clothes before leaving worksite.

Signs

"Warning," "Lead Work Area," "Poison" and "No Smoking or Eating." These signs shall be illuminated and cleaned as necessary to ensure legibility Containers of contaminated personal protective clothing and equipment should also be labeled as follows: CAUTION: CLOTHING CONTAMINATED WITH LEAD. DO NOT REMOVE DUST BY BLOWING OR SHAKING. DISPOSE OF LEAD CONTAMINATED WASH WATER IN ACCORDANCE WITH APPLICABLE REGULATIONS.
Commonly Asked Questions
Q. Is lead poisoning reversible?
A. Medical treatment may reduce the amount of lead in the bloodstream; however the damage which as already occurred to the person is irreversible. This is why prevention is so important.
Q. Can lead poisoning be prevented?
A. Lead poisoning can be prevented in a variety of ways.
Educate public and health professionals as the hazards of lead poisoning and how to prevent it. The third is to get tested and seek treatment if necessary
Lead in Action

Lead exposure occurs in a variety of industries including primary and secondary lead smelting, automotive manufacturing, shipbuilding and repair, and solder manufacturing. Although the OSHA PEL is 50µg/m3, also implements an “action level” for lead of 30µg/m3 where the employer is required to fulfill certain requirements of the standard such as exposure monitoring, medical surveillance and training and education but not others. For example, if initial monitoring reveals lead levels above the “action level” but below the “PEL”, the employer is required to repeat monitoring every six months; if lead is detected above the PEL, the employer would be required to repeat monitoring quarterly (every three months).

How Lead is Absorbed into the Body

When lead is absorbed into the body in certain doses (above the action level or PEL) it can be toxic. Although there are some immediate effects that occur from prolonged exposure to lead in those doses, some of the most serious toxic effects may not become apparent until several years after initial exposure.

There is a common misconception that lead can be absorbed through skin; lead itself is not normally absorbed through the skin Lead is absorbed into the body through inhalation (breathing) and ingestion (eating). When lead is present in the air as a dust, fume or mist it can be inhaled through your lungs and upper respiratory tract. The most common source of lead absorption in industry is inhalation. Generally, lead that is absorbed through ingestion stems from using or handling a product that may contain lead such as make-up, cigarettes, chewing tobacco or food.

Once lead is absorbed into the bloodstream, it circulates throughout the body and is stored in various organs and body tissue. While some of the lead will excrete, some will stay in the organs and body tissue. As the exposure to lead continues, the amount stored in the body increases, while the amount you excreted decreases. Lead stored in the tissues slowly causes irreversible damage to the individual cells then to the organs and eventually all body systems.

If certain levels of lead are reached in the bloodstream, an employee may have to be removed from the work area until the blood level returns to normal.