Heavy metal-Lead(Pb)

Overview:

Lead overexposure is one of the most common overexposures found in industry and is a leading cause of workplace illness. The reduction of lead exposure is a high strategic priority. OSHA five year strategic plan sets a performance goal of a 15% reduction in the average severity of lead exposure or employee blood lead levels in selected industries and workplaces.

Process, Control & Technical Information:

The following information that describes facility-specific information concerning processes and controls are maintained as an addendum to this written program:

a. Description of each operation in which lead is emitted; e.g. machinery used, material processed, controls in place, crew size, employee job responsibilities, operating procedures, and maintenance practices.

b. Description of the specific means used to achieve compliance, including engineering plans and studies used to determine methods selected for controlling exposure to lead.

c. report of the technology considered in meeting the permissible exposure limit;

d. Air monitoring data which documents the source of lead emissions;

e. A detailed schedule for implementation of this program, including documentation such as copies of purchase orders for equipment, construction contracts, etc.

f. Records of Employee Training and Notifications

g. Specific work practice program and controls for each operation involving lead exposure

h. Administrative control schedule

i. All other relevant information

Hazards:

Pure lead (Pb) is a heavy metal at room temperature and pressure and is a basic chemical element. It can combine with various other substances to form numerous lead compounds. The Permissible Exposure Limit (PEL) set by OSHA is 50 micrograms of lead per cubic meter of air (50 ug/m(3)), averaged over an 8-hour workday. Lead can be absorbed by inhalation (breathing) and ingestion (eating). Lead is not absorbed through your skin. When lead is scattered in the air as dust, fume, or mist it can be inhaled and absorbed through the lungs and upper respiratory tract. Lead can also be absorbed through the digestive system if swallowed. Handling food, cigarettes, chewing tobacco, or make-up which have lead contamination or handling them with hands contaminated with lead, will contribute to ingestion. A significant portion of inhaled or ingested lead goes into the bloodstream. Once in the bloodstream, lead is circulated throughout the body and stored in various organs and body tissues. Some of this lead is quickly filtered out of the body and excreted, but some remains in the blood and other tissues. As exposure to lead continues, the amount stored in the body will increase. Lead stored in body tissues can cause irreversible damage, first to individual cells, then to organs and whole-body systems.

Short-term (acute) effects of overexposure to lead:

Lead is a potent, systemic poison. Taken in large enough doses, lead can kill in a matter of days. A condition affecting the brain called acute encephalitic may arise which develops quickly to seizures, coma, and death from cardiorespiratory arrest. There is no sharp dividing line between rapidly developing acute effects of lead and chronic effects that take longer to acquire. Lead adversely affects numerous body systems, and causes forms of health impairment and disease which arise after periods of exposure as short as days or as long as several years.

Long-term (chronic) effectiveness of overexposure to lead:

Chronic overexposure to lead may result in severe damage to blood-forming, nervous, urinary, and reproductive systems. Some common symptoms of chronic overexposure include loss of appetite, metallic taste in the mouth, anxiety, constipation, nausea, pallor, excessive tiredness, weakness, insomnia, headache, nervous irritability, muscle, and joint pain or soreness, fine tremors, numbness, dizziness, hyperactivity, and colic. In lead colic, there may be severe abdominal pain.

Monitoring:

Initial determination.

The company has made an initial determination of lead work areas and exposure levels and will conduct subsequent "initial determinations" in the event of changes to hazard control methods or operational processes that affect an employee or environmental exposure. Initial determinations are conducted to determine if any employee may be exposed to lead at or above the action level of 30 micrograms per cubic meter of air (30 ug/m(3)) averaged over an 8-hour period.

Where a determination is made that no employee is exposed to airborne concentrations of lead at or above the action level, the company shall maintain a written record. The record shall include quantitative sampling data, date of determination, location within the worksite, and the name and social security number of each employee monitored.

Monitoring requirements:

• Monitoring and analysis methods shall have an accuracy (to a confidence level of 95%) of not less than plus or minus 20 percent for airborne concentrations of lead equal to or greater than 30 ug/m(3).
• Where a determination shows the possibility of any employee exposure at or above the action level, the company shall conduct monitoring which is representative of the exposure for each employee in the workplace or process area who is exposed to lead.
• For the purposes of monitoring requirements, employee exposure is that exposure that would occur if the employee were not using a respirator.
• Monitoring and sample collection shall cover full shift (for at least 7 continuous hours) personal samples including at least one sample for each shift for each job classification in each work area.
• Full shift personal samples must be representative of the monitored employee's regular, daily exposure to lead.

Monitoring Frequency:

At or Above Action Level and Below PEL:

Every 6 months ff the initial determination or subsequent monitoring reveals employee exposure to be at or above the action level but below the permissible exposure limit. This monitoring (6-month frequency) will continue until at least two consecutive measurements, taken at least 7 days apart, are below the action level.

Above PEL:

If the initial monitoring reveals that employee exposure is above the permissible exposure limit the company will repeat monitoring quarterly. Quarterly monitoring will continue until at least two consecutive measurements, taken at least 7 days apart, are below the PEL but at or above the action level.

Additional monitoring:

Whenever there has been a production, process, control, or personnel change that may result in new or additional exposure to lead, or whenever any other reason to suspect a change which may result in new or additional exposures to lead, additional monitoring will be conducted.

Health Effects

Workers today are still being exposed to lead that results in adverse health effects.?Recent studies have provided evidence that lead can cause health effects at blood lead levels lower than those established by OSHA’s 1978 Lead standard.

Epidemiological and experimental studies indicate that chronic exposure resulting in blood lead levels (BLL) as low as 10 μg/dL in adults are associated with impaired kidney function, high blood pressure, nervous system, and behavioral effects, cognitive dysfunction later in life, and subtle cognitive effects attributed to prenatal exposure.?Pregnant women need to be especially concerned with reducing BLL since this can have a serious impact on the developing fetus.

Chronic exposures leading to BLLs above 20 μg/dL can cause sub-clinical effects on cognitive functions as well as adverse effects on sperm/semen quality and delayed conception.?BLLs between 20 to 40 μg/dL are associated with effects such as cognitive aging as well as deficits in vasomotor dexterity, lower reaction times, and attention deficit.?At BBLs above 40 μg/dL, workers begin to experience symptoms such as headache, fatigue, sleep disturbance, joint pain, anorexia, and constipation.

Engineering Controls:

Where any employee is exposed to lead above the permissible exposure limit for more than 30 days per year, the company will implement feasible engineering and work practice controls (including administrative controls) to reduce and maintain employee exposure to lead. Wherever the engineering and work practice controls which can be instituted are not sufficient to reduce employee exposure to or below the permissible exposure limit, the company will still use them to reduce exposures to the lowest feasible level and shall supplement them by the use of respiratory protection. Where any employee is exposed to lead above the permissible exposure limit, but for 30 days or less per year, the company will implement engineering controls to reduce exposures to 200 ug/m(3), but thereafter may implement any combination of engineering, work practice (including administrative controls), and respiratory controls to reduce and maintain employee exposure to lead to or below 50 ug/m(3).

Mechanical ventilation:

When ventilation is used to control exposure, measurements that demonstrate the effectiveness of the system in controlling exposure, such as capture velocity, duct velocity, or static pressure shall be made at least every 3 months. Measurements of the system's effectiveness in controlling exposure shall be made within 5 days of any change in production, process, or control which might result in a change in employee exposure to lead.

Recirculation of air. If air from exhaust ventilation is recirculated into the workplace, the system must include:

• a high-efficiency filter with reliable backup filter; and
• controls to monitor the concentration of lead in the return air and to bypass the recirculation system automatically if it fails are installed, operating, and maintained.

Administrative Controls:

If administrative controls are used as a means of reducing employees TWA exposure to lead, the company shall establish and implement a job rotation schedule which includes:

• Name or identification number of each affected employee,
• Duration and exposure levels at each job or work station where each affected employee is located.
• Other information which may be useful in assessing the reliability of administrative controls to reduce exposure to lead Administrative control information and records will be maintained as an addendum to this written program.

Respirators:

When respirators are used to supplement engineering and work practice controls to comply with the PEL and all other requirements have been met, employee exposure, for the purpose of determining compliance with the PEL, may be considered to be at the level provided by the protection factor of the respirator for those periods the respirator is worn. Those periods may be averaged with exposure levels during periods when respirators are not worn to determine the employee's daily TWA exposure. The respiratory protection program will be conducted in accordance with 29 CFR 1910.134 (b) through (d) (except (d)(1)(iii)), and (f) through (m). The company will provide a powered air-purifying respirator when an employee chooses to use this type of respirator and such a respirator provides adequate protection to the employee.

Respirators must be used during:

• Periods necessary to install or implement engineering or work practice controls.
• Work operations for which engineering and work practice controls are not sufficient to reduce employee exposures to or below the permissible exposure limit.
• Periods when an employee requests a respirator

Protective Clothing & Equipment:

If an employee is exposed to lead above the PEL, without regard to the use of respirators or where the possibility of skin or eye irritation exists, the company will provide at no cost to the employee appropriate protective work clothing and equipment such as, but not limited to:

• Coveralls or similar full-body work clothing;
• Gloves, hats, and shoes or disposable shoe coverlets; and
• Face shields, vented goggles, or other appropriate protective equipment.

Housekeeping:

• All surfaces shall be maintained as free as practicable of accumulations of lead.
• Floors and other surfaces where lead accumulates may not be cleaned by the use of compressed air.
• Shoveling, dry or wet sweeping, and brushing may be used only where vacuuming or other equally effective methods have been tried and found not to be effective.
• Where vacuuming methods are used, the vacuums shall be used and emptied in a manner that minimizes the reentry of lead into the workplace.

Hygiene Facilities & Practices:

The following is requirements pertain to all areas where employees are exposed to lead above the PEL, without regard to the use of respirators:

• No storage or consumption of food or beverages.
• No tobacco product storage or use.
• No cosmetics stored or used.
• No personal clothing or articles, except in authorized change areas

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