Request for Assistance in Preventing Lead Poisoning in Construction Workers
DHHS (NIOSH) Publication Number 91-116a
WARNING! Lead poisoning may occur in workers during abrasive blasting, sanding, cutting, burning, or welding of bridges and other steel structures coated with lead-containing paints.
The National Institute for Occupational Safety and Health (NIOSH) requests assistance in preventing the lead poisoning *of workers engaged in the maintenance, repainting, or demolition of bridges or other steel structures coated with lead-containing paints. NIOSH recently learned of 42 workers who developed lead poisoning while working on bridges. Operations such as abrasive blasting, sanding, burning, cutting, or welding on steel structures coated with lead-containing paints may produce very high concentrations of lead dust and fumes. Furthermore, the recent introduction of containment structures (enclosures designed to reduce environmental contamination by capturing particles of paint and used blasting material) may result in even higher airborne concentrations of lead. Lead dust at the worksite may also result in contamination of workers’ homes and automobiles.
For the construction industry, NIOSH and the Occupational Safety and Health Administration (OSHA) have recently recommended that exposure to lead dust and fumes be minimized by the use of engineering controls and work practices, and by the use of personal protective equipment (PPE)–including respirators–for additional protection [OSHA/NIOSH 1991]. Airborne lead concentrations and blood lead concentrations should be monitored to determine the effectiveness of controls and PPE. All new contracts for Federal, State, and local departments of transportation should include specifications for a mandatory program of worker protection from lead poisoning during the maintenance, repainting, or demolition of bridges and other steel structures.
NIOSH requests that the recommendations in this Alert be brought to the attention of workers and employers (including subcontractors) by general construction contractors, State departments of transportation (including worksite inspectors), labor union representatives, labor associations, editors of appropriate trade journals, and safety and health officials. Your assistance in this effort will help to achieve one of the national health objectives specified by Healthy People 2000 [DHHS 1990], a statement of national goals for health promotion and disease prevention. These goals are the product of a national effort involving State health departments, national organizations, and many individuals. The goal for workers exposed to lead is to eliminate exposures that result in blood lead concentrations greater than 25 µg/dl of whole blood.
Workers are potentially exposed to lead during work on bridges or other steel structures such as water and fuel storage tanks. Workers who may be exposed to lead include abrasive blasters, inspectors, iron workers (welders and cutters), painters, and laborers. In 1987, an estimated 44,000 persons worked in bridge, tunnel, and elevated-highway construction (Standard Industrial Classification Code [SIC] 1622), and an estimated 14,000 persons worked in wrecking and demolition (SIC 1795) [Bureau of the Census 1990].
An estimated 90,000 bridges in the United States are coated with lead-containing paints [Katauskas 1990]. According to a survey of State departments of transportation, lead-containing coatings were found on approximately 77% of U.S. bridges that were repainted between 1985 and 1989 [Steel Structures Painting Council 1991].
Maintenance of Steel Structures
Before a new coating may be applied to bridges and other steel structures, deteriorated paint and corrosion must be removed and the metal surface must be properly prepared [Katauskas 1990]. In addition, all coatings of lead-based paints must be removed before another type of paint can be applied [Katauskas 1990]. This process is most commonly accomplished by using a portable device for abrasive blast cleaning. These devices are designed to deliver a high-velocity stream of abrasive to the metal surface. Compressed air is generally used, but some devices use water to deliver the abrasive. A variety of nonmetallic and metallic abrasives have been used, including silica sand, slag, and steel grit. The worker performing the blasting directs the blasting nozzle at the surface to be cleaned. As the paint is removed, small particles become airborne, and the used abrasives become contaminated with lead-containing particles.
Containment structures are used to reduce the release of lead into the environment by capturing paint chips, dust, and used abrasive. Where possible, containment structures are designed so that the used abrasives and debris are directed through chutes or tubes into a barge or hopper. Because the recovery systems in the containment structures are not completely effective, some of the material must be recovered manually by sweeping, shoveling, or vacuuming. Under the Resource Conservation and Recovery Act (RCRA), waste material must be tested, and if the leachable lead concentration is 5 parts per million (ppm) or greater, the material is classified as a hazardous waste [40 CFR** 260].
Containment structures are designed to reduce the dispersion of lead into the environment, but they may increase worker exposure to airborne lead. Current techniques for containment are not well defined and vary in their efficiency in preventing lead from being released into the environment. Some containment structures consist of tarpaulins or open mesh fabrics placed over the blasting area; some use rigid materials of wood, metal, or plastic to enclose the blasting area; and some use a combination of flexible and rigid materials. Large air-moving devices may be mounted on trucks and connected to the containment structures to exhaust dust-laden air. The exhausted air is passed through dust separation devices and filters before it is released to the atmosphere. This ventilation technique may also create a negative pressure within the containment structure and help reduce environmental contamination.
Workers may receive additional exposure at some sites when the containment structures (which may contain residual lead dust and debris) are disassembled and moved. Workers should be adequately protected while performing these operations.
Potential for Exposure to Airborne Lead
At sites where workers performed bridge, tunnel, and elevated-highway construction (SIC 1622), OSHA reported airborne lead concentrations exceeding 200 micrograms per cubic meter (µg/m3) for 65% of the samples collected between April 1984 and April 1988 [OSHA 1988]. Tables 1 and 2 summarize cases of occupational exposures to lead reported during abrasive blasting, sanding, burning, cutting, and welding. Most of the operations described were conducted outside containment structures. These data indicate that persons working at the jobsite outside the containment structure are also at risk of exposure to lead. Workers who do not shower and change into clean clothing before leaving the worksite may contaminate their homes and automobiles with lead dust. Other members of the household may then be exposed to harmful amounts of lead [Grandjean and Bach 1986; Kaye et al. 1987; Matte et al. 1989; Baker et al. 1977].
|Operation||Job||Exposure range during task (µg/m3)||Comments|
|Bridge rehabilitation [New Jersey Department of Health 1988a]||Torch burner||220-6,000||Work conducted in semiconfined area|
|Hammering and drilling||40-360||Workers were mechanically disturbing painted surface in semiconfined area|
|Bridge demolition (no containment structure) [New Jersey Department of Health 1988b]||Torch burner||110-1,200||Workers were cutting beams on bridge|
|Burner helper||330||These workers assisted burners who were cutting the bridge|
|Power tool use||5-50|
|Bridge demolition (no containment structure) [New Jersey Department of Health 1990]||Burner||180-1,800||—|
|Paint removal from boiler (no containment structure) [Adkinson 1989]||Blaster||230-860||Samples were taken inside respirator|
|640-1,400||Samples were taken outside respirator|
|Power tool operators||80-790||Workers were spot-cleaning an existing surface|
|Power plant (no containment structure) [Rekus 1988]||Burner||2,100-
|Bridge repair (no containment structure) [Rekus 1988]||Welder||2,200-4,200||—|
|Paint removal from a tank [Lippy et al. 1988]||Abrasive blasting||490-870||Work conducted inside containment structure|
|Carpenter||8||Work conducted outside containment structure|
|Steam filter||40-50||Work conducted outside containment structure|
|Blaster helper||90-560||Work conducted inside containment structure|
|Case No.*||Location and description||Job||Range of airborne lead concentration during task (µg/m3)||Comments|
|1||Connecticut, paint removal from bridge (with containment structures)||Blaster||4-540||Work conducted inside containment structure|
|[area samples]||230-410||Work conducted outside containment structure|
|3||Louisiana, paint removal from bridge (with containment structures)||Blaster||2-730||Work conducted inside containment structure|
|5||New York, bridge demolition||Burners||600-4,000||—|
|6||Kentucky, paint removal from bridge (with containment structures)||Blaster||3,690-29,400||Work conducted inside containment structure; samples taken outside respirator|
|Blaster||9-190||Work conducted inside containment structure; samples taken inside respirator|
|Groundsman||5-6,720||Work conducted outside containment structure|
|* No samples were collected for cases 2 and 4. [Return to top of table]|
Health Effects of Lead Exposure
The frequency and severity of medical symptoms increase with the concentration of lead in the blood. Many adults with blood lead levels (BLLs) of 80 µg/dl or greater have symptoms or signs of acute lead poisoning, although in some individuals, symptoms may be so mild that they are overlooked [NIOSH 1978; Rosenstock and Cullen 1986]. Common symptoms of acute lead poisoning are loss of appetite, nausea, vomiting, stomach cramps, constipation, difficulty in sleeping, fatigue, moodiness, headache, joint or muscle aches, anemia, and decreased sexual drive. Severe health effects of acute lead exposure include damage to the nervous system, including wrist or foot drop, tremors, and convulsions or seizures. Acute lead poisoning from uncontrolled occupational exposures has resulted in fatalities [Hayhurst 1915].
Chronic lead poisoning may result after lead has accumulated in the body over time, mostly in the bone. Long after exposure has ceased, some physiological event such as illness or pregnancy may release this stored lead from the bone and produce adverse health effects such as impaired hemoglobin synthesis, alteration in the central and peripheral nervous systems, hypertension, effects on male and female reproductive systems, and damage to the developing fetus [Landrigan 1989]. These health effects may occur at BLLs below 50 µg/dl.
Relevant Exposure Criteria and Regulations
In 1978, OSHA promulgated a comprehensive standard regulating occupational exposure to inorganic lead in general industry [29 CFR 1910.1025]. Under this standard, the permissible exposure limit (PEL) for inorganic lead is 50 µg/m3 of air as an 8-hour time weighted average (TWA). However, the construction industry was exempted from this regulation and has a 200-µg/m3 PEL for inorganic lead [29 CFR 1926.55]. Unlike the OSHA standard for general industry, the construction standard does not require medical monitoring of workers exposed to lead or removal of workers from the job when they show elevated concentrations of lead in the blood. Specific medical monitoring recommendations for these workers are discussed in the section on conclusions and recommendations.
The NIOSH recommended exposure limit (REL) for lead is less than 100 µg/m3 of air as a TWA for up to 10 hours per day during a 40-hour workweek. This air concentration is to be maintained so that the worker’s lead concentration remains below 60 µg/100 grams of whole blood (approximately equivalent to 60 µg/dl) [NIOSH 1988c; CDC 1990]. NIOSH is presently reviewing the data on the health effects of lead to determine whether our current recommendations need to be updated.
Several States have instituted programs to protect construction workers from the hazards of occupational lead exposure. For example, Maryland enacted in 1984 (and modified in 1988) a comprehensive standard regulating occupational lead exposure in construction work [Maryland Regulations Code 1988]. Under this standard, the permissible exposure limit for lead is 50 µg/m3 as an 8-hour TWA. This standard must be incorporated in all contracts involving bridge work in Maryland. Connecticut is currently preparing similar requirements for inclusion in contracts [Connecticut Department of Transportation 1991].
CASE REPORTS OF LEAD POISONING
NIOSH recently learned of 42 construction workers at 8 different worksites who developed lead poisoning (BLLs exceeding 50µg/dl of blood) while working on bridges [Mintz 1990; Rae 1990; Johnson 1990; CDC 1989; Marino et al. 1989; NIOSH 1991b]. The BLLs for these workers ranged from 51 to 160 µg/dl. The mean BLL for the U.S. population is 13.9 µg/dl, and the upper 95th percentile is 25.0 µg/dl [NCHS 1984]. The airborne concentrations of lead ranged from 2 to 29,400 µg/m3 (see Table 2). At least 26 of the 42 cases of lead poisoning (62%) were workers employed at a site using a containment structure. The actual number of cases of occupational lead poisoning nationwide is much larger than 42, but it cannot be accurately determined since employers are not required to routinely measure lead concentration in the blood of exposed construction workers.
Case No. 1
A study now being conducted in Connecticut has identified four workers with lead poisoning at three different bridge sites [Mintz 1990]. Containment structures were used at all three sites. The workers’ BLLs ranged from 51 to 66 µg/dl, but none reported symptoms of lead intoxication. Personal breathing zone samples indicated airborne lead concentrations of 4 to 640 µg/m3. All workers wore respiratory protection (abrasive blasting, half-mask, or disposable respirators).
Case No. 2
In 1989, eight workers at a bridge site in Monroe, Louisiana, developed lead poisoning while working in a containment structure [Rae 1990]. The BLLs of these workers ranged from 56 to 146 µg/dl. Their complaints included malaise, arm numbness, abdominal discomfort, joint and muscle aches, headache, and diarrhea. Airborne concentrations of lead were not reported.
Case No. 3
In May 1990, 12 bridge workers in Baton Rouge, Louisiana, developed lead poisoning while working in a containment structure [Johnson 1990]. The BLLs of affected workers ranged from 52 to 102 µg/dl. Reported airborne concentrations of lead ranged from 2 to 730 µg/m3. The worker with the BLL of 102 µg/dl developed joint pains and required hospitalization for intravenous chelation therapy.
Case No. 4
In March 1988, five workers developed lead poisoning during demolition of a bridge in Massachusetts [CDC 1989]. The BLLs of affected workers ranged from 67 to 160 µg/dl. All five workers reported symptoms consistent with lead poisoning. Four of the five workers were treated with intravenous chelation therapy. Airborne lead concentrations were not reported.
Case No. 5
In 1987, 11 workers who wore positive-pressure, air supplied respirators developed lead poisoning during demolition of a bridge in New York [Marino et al. 1989]. The BLLs of these workers ranged from 52 to 120 µg/dl. One worker with a BLL of 120 µg/dl reported symptoms of muscle soreness, weakness, lack of appetite, nausea, and vomiting. Another worker with a BLL of 105 µg/dl reported symptoms of headache, tiredness, and abdominal discomfort. Both workers required intravenous chelation therapy. Personal breathing zone concentrations of lead ranged from 600 to 4,000 µg/m3.
Case No. 6
In March 1991, NIOSH investigators began a study of lead exposures in 12 workers engaged in abrasive blasting and repainting of a bridge in Kentucky [NIOSH 1991b]. BLLs were measured during the first week of work and ranged from 5 to 48 µg/dl. The BLLs were measured again after 1 month of exposure and ranged from 9 to 61 µg/dl. Two workers had BLLs exceeding 50 µg/dl. The airborne concentration of inorganic lead ranged from 5 to 29,400 µg/m3. Blasters wore continuous flow abrasive blasting respirators. Other workers used half-mask, air-purifying respirators with high-efficiency particulate air (HEPA) filters. However, there was no complete respiratory protection program consistent with OSHA requirements [29 CFR 1910.134] and NIOSH recommendations [NIOSH 1987a; NIOSH 1987b]. Running water, coveralls, and clean change-rooms were not available at the site.
Conclusions and Recommendations
Lead poisoning may occur when workers inhale or ingest lead dust and fumes during abrasive blasting, sanding, cutting, burning, or welding of bridges and other steel structures coated with lead-containing paints. Data presented in this document reveal lead poisoning among workers who were wearing respirators. Therefore, a prudent policy is to minimize the risk of adverse health effects by keeping lead concentrations as low as possible and by using all available controls–including engineering controls, work practices, and respiratory protection. To help achieve the Healthy People 2000 [DHHS 1990] objective of limiting worker blood lead concentrations to 25 µg/dl, NIOSH recommends the following measures for reducing lead exposure and preventing lead poisoning among workers involved in demolishing or maintaining bridges and other steel structures.
An industrial hygienist or other qualified professional should perform an initial hazard assessment of the worksite to determine the composition of the paint. Environmental monitoring should also be performed to (1) measure worker exposure to airborne lead and other hazardous agents (e.g., silica and solvents), and (2) select the engineering controls and PPE required. Environmental monitoring should be performed as needed to measure the effectiveness of controls and to determine whether the proper respiratory protection is being worn. Air samples should be collected and analyzed according to NIOSH methods [NIOSH 1984] or their equivalent.
Engineering controls should be used to minimize exposures to lead at the worksite. At a minimum, airborne lead exposures should not exceed the current OSHA PEL for general industry (50 µg/m3). Wherever possible, engineering controls should include material substitution (i.e., repainting of structures with less toxic material), process and equipment modification, isolation or automation, and local and general exhaust ventilation. The appropriate types of controls vary with the operation.
Welding, Cutting, or Burning
Before welding, cutting, or burning any metal coated with lead-containing materials, remove the coating to a point at least 4 inches from the area where heat will be applied [29 CFR 1926.354]. When removal of lead-containing paint is not feasible, use engineering controls (e.g., local exhaust ventilation) to protect workers who are welding, cutting, or burning lead-bearing materials. Such controls should be used to remove fumes and smoke at the source and to keep the concentration of lead in the breathing zone below the OSHA PEL. Contaminated air should be filtered before it is discharged into the environment well away from the source of intake air and other workers. Replace contaminated air with clean air [29 CFR 1926.353].
When performing abrasive blasting, scaling, chipping, grinding, or other operations to remove lead-containing paint, use work practices that minimize the amount of dust generated. Less dusty blasting techniques include centrifugal blasting (using rotating blades to propel the abrasive, which is recovered and recycled), wet blasting (using high-pressure water with or without an abrasive, or surrounding the blast nozzle with a ring of water), and vacuum blasting (shrouding the nozzle with local exhaust ventilation) [Rex 1990]. Other methods that reduce dust include scraping, heating and scraping, use of needle guns, and chemical removal.
Materials containing crystalline silica should not be used as abrasives for any blasting operation, including paint removal [NIOSH 1988b]. Crystalline silica is associated with silicosis and is classified by NIOSH as a potential occupational carcinogen [NIOSH 1988d].
Lead-containing dust and abrasive materials should be removed daily by using vacuums equipped with HEPA filters or by using wet methods to prevent lead-containing particles from becoming airborne [Steel Structures Painting Council 1991].
Work Inside Containment Structures
Containment structures are often used to reduce environmental contamination by capturing particles of paint and used blasting materials. Although such structures reduce environmental contamination, they may also increase lead exposures for workers (see Figure 1). Ventilation should be provided to reduce the airborne concentration of lead and increase visibility. Containment structures should be designed to optimize the flow of ventilation air past the worker(s). Insofar as possible, workers should be upstream from the blasting operation to reduce exposure to lead dust entrained in the ventilation air and to improve visibility. Designs for the containment structure and ventilation systems should be specific to each task because of varied conditions at the worksite (i.e., the type of steel structure being blasted, the type of blasting methods, and the type of materials used for construction).
Figure 1. Construction worker using a HEPA-filter vacuum inside a containment structure. Note that the worker is obscured by a high airborne concentration of dust.
All new contracts of Federal, State, and local departments of transportation should include specifications for a mandatory program of worker protection from lead poisoning during the maintenance, repainting, or demolition of bridges and other steel structures.
Personal Hygiene Practice
Personal hygiene is an important element of any program for protecting workers from exposure to lead dust [Ulenbelt et al. 1990]. OSHA requires employers to provide adequate washing facilities at the worksite so that workers can remove lead particles that accumulate on the skin and hair [29 CFR 1926.51]. Showers should also be available [OSHA/NIOSH 1991].
All workers exposed to lead should wash their hands and faces before eating, drinking, or smoking, and they should not eat, drink, or use tobacco products in the work area. Tobacco products (cigarettes, cigars, chewing tobacco, etc.) and food items should not be permitted in the work area. Contaminated work clothes should be removed before eating.
Workers should change into work clothes at the worksite. Work clothes include disposable or washable coveralls. Street clothes should be stored separately from work clothes in a clean area provided by the employer. Separate lockers or storage facilities should be provided so that clean clothing is not contaminated by work clothing and shoes. Workers should change back into their street clothes after washing or showering and before leaving the worksite to prevent the accumulation of lead dust in the workers’ cars and homes and thereby protect family members from exposure to lead. Cars should be parked where they will not be contaminated with lead.
Employers should arrange for the laundering of protective clothing; or, if disposable protective clothing is used, the employer should maintain an adequate supply at the worksite and arrange for its safe disposal according to applicable Federal [40 CFR 260] and State regulations.
Warning signs should be posted to mark the boundaries of lead-contaminated work areas. These signs should follow the example presented in the OSHA general industry standard [29 CFR 1910.1025], which warns about the lead hazard and prohibits eating and drinking in the area. Such signs should also specify any PPE required (for example, respirators). The sample sign in Figure 2 contains all the information needed for a lead-contaminated work area where respirators are required.
Figure 2. Sample of warning sign for lead work area requiring respirators.
Personal Protective Equipment (PPE)
Engineering controls and good work practices should be used to minimize worker exposure to lead. Because of the variable exposure concentrations in the construction industry and the difficulty of monitoring a mobile workforce, PPE should be used whenever workers are potentially exposed to lead [OSHA/NIOSH 1991]. The use of PPE should supplement the continued use of engineering controls and good work practices.
Protective clothing not only shields workers from the hazards of welding and abrasive blasting, but it also minimizes the accumulation of lead on the worker’s skin and hair. Workers should change into washable coveralls or disposable clothing before entering the contaminated work area. Because wearing PPE (especially protective clothing) can contribute to the development of heat stress [NIOSH/OSHA/USCG/EPA 1985], a potentially serious illness, regular monitoring and other preventive measures are vital [NIOSH 1986].
To minimize the amount of lead that may accumulate in the worker’s car and home and to protect the members of the worker’s household, lead-contaminated clothing (including work shoes) should be left at the worksite for cleaning or disposal. Workers who are welding, cutting, or burning should wear nonflammable clothing [NIOSH 1988a].
Effective source control measures (such as containment or local exhaust ventilation) should be implemented to minimize worker exposure to lead. NIOSH prefers such measures as the primary means of protecting workers; but source control at construction sites is often ineffective, and airborne lead concentrations may be high or may vary unpredictably. Therefore, respiratory protection is also necessary for certain operations such as blasting, sweeping, and vacuuming, and for other jobs as determined at the worksite by an industrial hygienist or other qualified professional. However, respirators are the least preferred method of controlling lead exposure, and they should not be used as the only means of preventing or minimizing exposures. The use of respirators should supplement the continued use of engineering controls and good work practices [OSHA/NIOSH 1991].
When respirators are used, the employer must establish a comprehensive respiratory protection program as outlined in the NIOSH Respirator Decision Logic [NIOSH 1987b] and the NIOSH Guide to Industrial Respiratory Protection [NIOSH 1987a], and as required in the OSHA respiratory protection standard [29 CFR 1910.134]. Important elements of the OSHA respiratory protection standard are (1) an evaluation of the worker’s ability to perform the work while wearing a respirator, (2) regular training of personnel, (3) periodic environmental monitoring, and (4) respirator fit testing, maintenance, inspection, cleaning, and storage. The program should be evaluated regularly by the employer. Without a complete respiratory protection program, workers will not receive the protection anticipated.
Respirators should be selected by the person who is in charge of the program and knowledgeable about the workplace and the limitations associated with each type of respirator. Because exposures to lead during construction may vary substantially throughout a workshift and between days, the highest anticipated exposure should be used to determine the appropriate respirator for each job.
Respirator selection should be made according to the guidelines in Table 3. Employers must use respirators that are certified by NIOSH and the Mine Safety and Health Administration (MSHA) [NIOSH 1991a].
|Condition||Minimum respiratory protection*|
|Less than or equal to 0.5 mg/m3 (10 x PEL**)||Any air-purifying respirator with a high-efficiency particulate filter|
|Less than or equal to 1.25 mg/m3 (25 x PEL)||Any powered, air-purifying respirator with a high-efficiency particulate filter, or
Any supplied-air respirator equipped with a hood or helmet and operated in a continuous-flow mode (for example, type CE abrasive blasting respirators)
|Less than or equal to 2.5 mg/m3 (50 x PEL)||Any air-purifying, full-facepiece respirator with a high efficiency particulate filter, or
Any powered, air-purifying respirator with a tight fitting facepiece and a high-efficiency particulate filter
|Less than or equal to 50 mg/m3 (1,000 x PEL)||Any supplied-air respirator equipped with a half-mask and operated in a pressure-demand or other positive pressure mode|
|Less than or equal to 100 mg/m3 (2,000 x PEL)||Any supplied-air respirator equipped with a full face-piece and operated in a pressure-demand or other positive-pressure mode|
|Planned or emergency entry into environments containing unknown concentrations or concentrations above 100 mg/m3 (2,000 x PEL)||Any self-contained breathing apparatus equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode, or
Any supplied-air respirator equipped with a full face-piece and operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained breathing apparatus operated in a pressure-demand or other positive-pressure mode
|Firefighting||Any self-contained breathing apparatus equipped with a full facepiece and operated in a pressure-demand or other positive pressure mode|
|Escape only||Any air-purifying, full- facepiece respirator with a high-efficiency particulate filter, or
Any appropriate escape-type, self-contained breathing apparatus
|* Only NIOSH/MSHA-approved equipment should be used. [Return to top of table]
** Multiple of the OSHA PEL for general industry. [Return to top of table]
NIOSH type CE respirators are required for use by abrasive blasting operators [29 CFR 1910.94]. Currently, only continuous-flow respirators are certified by NIOSH for abrasive blasting [29 CFR 1910.94], but positive-pressure, supplied-air respirators would provide greater protection [NIOSH 1987b; 30 CFR 11]. The continuous-flow respirators are recommended by NIOSH only for airborne concentrations less than or equal to 25 times the OSHA PEL for general industry–50 µg/m3 [NIOSH 1987b]. Furthermore, manufacturer’s instructions regarding quality of air, air pressure, and inside diameter and length of hoses must be strictly followed. Use of longer hoses, hoses having a smaller inside diameter, or hoses with kinks and bends may restrict the flow of air to the respirator.
In all cases, respiratory protection should be donned before entering the contaminated work area, and it should be removed only after the worker has left that area.
BLLs are currently the best indicator of personal lead exposure. Workers potentially exposed to lead should therefore be monitored for the presence of lead in blood and the effects of lead on the blood-forming system. This assessment is necessary to ensure that engineering controls, personal hygiene practices, and PPE are preventing lead exposure.
The OSHA general industry standard contains provisions for the medical monitoring of workers exposed to lead [29 CFR 1910.25]. NIOSH supports the use of these provisions for construction workers but acknowledges that these workers may require more frequent blood lead monitoring (for example, monthly) than specified in the OSHA standard because of their highly variable, unpredictable exposures to lead. Similar provisions for more frequent monitoring have also been specified by the Connecticut Department of Transportation to be included in bid specifications for construction work involving lead exposure [Connecticut Department of Transportation 1991].
Lead concentration in the blood should be measured for any exposed worker who experiences symptoms or signs of lead poisoning. Analyses of blood should be performed only by OSHA-listed laboratories (a listing is available from the OSHA Analytical Laboratory in Salt Lake City, Utah; telephone, 801-524-4270).
The results of all laboratory analyses, a description of the worker’s job, and any available data on possible exposures should be evaluated by a physician with experience and training in occupational health. To detect the health effects of excess lead exposure and to provide a baseline for comparison with future results, an occupational health interview and a physical examination should be performed before job placement, before returning to work after being removed from the job because of elevated blood lead concentrations, and annually for all workers exposed to lead.
The OSHA lead standard for general industry [29 CFR 1910.1025] requires that certain actions be taken at given concentrations of lead in the blood (see Table 4). These actions are designed to prevent many of the adverse health effects of lead exposure.
|Number of tests||BLL* (µg/dl)||Action required|
|1||Greater than or equal to 40||Notification of worker in writing; medical examination of worker and consultation|
|3 (average)||Greater than or equal to 50||Removal of worker from job with potential lead exposure|
|1||Greater than or equal to 60||Removal of worker from job with potential lead exposure|
|2||Less than 40||Reinstatement of worker in job with potential lead exposure|
|* In the OSHA general industry standard for lead, BLLs are reported in micrograms per 100 grams (µg/100 g) of whole blood, which is approximately equal to µg/dl. [Return to top of table]|
Presently, 15 States require laboratories and health care providers to report cases of elevated blood lead concentrations to the State health department [Freund et al. 1989]. Table 5 provides a list of the States that require such reporting for each State. To monitor progress in achieving the Healthy People 2000 objective for lead concentrations in blood [DHHS 1990], cases of elevated BLLs should be reported to all State health departments.
|State||Contact person||Concentration that requires reporting (µg/dl)|
|Alabama||Charles Woernle, M.D., M.P.H.
Department of Public Health
434 Monroe Street
Montgomery, AL 36130
|California||Neil Maizlish, Ph.D.
Occupational Health Program
California Department of Health Services
2151 Berkeley Way, Room 504
Berkeley, CA 94704
Colorado Department of Health
4210 E. 11th Avenue
Denver, CO 80220
|Connecticut||Narda Tolentino, M.P.H.
Connecticut Department of Health Services
Environmental Epidemiology and Occupational Health (EEOH)
150 Washington Street
Hartford, CT 06106
Occupational Disease Registry
Illinois Department of Public Health
Division of Epidemiologic Studies
605 W. Jefferson
Springfield, IL 62761
Environmental Epidemiology Section
Iowa Department of Public Health
Lucas State Office Building
Des Moines IA 50319
|Maryland||Ellen Coe, R.N., M.P.H.
Health Registries Division
Maryland Department of the Environment
2500 Broening Highway
Baltimore, MD 21224
301-631-3851, FAX 301- 631-3198
Massachusetts Department of Labor and Industries
Division of Occupational Hygiene
1001 Watertown Street
Newton, MA 02165
|Michigan||Larry Chadzynski, R.S., M.P.H.
Office of the Director
Michigan Department of Public Health
3423 N. Logan/Martin Luther King Blvd.
P.O. Box 30195
Lansing, MI 48909
|New Jersey||Barbara Gerwel, M.D.
Occupational Disease Prevention Program
New Jersey Department of Health
C N 360, John Fitch Plaza
Trenton, NJ 08625
|New York||Robert Stone, Ph.D.
New York State Department of Health
2 University Place–Room 155
Albany, NY 12203-3313
|Oregon||Jane Gordon, Ph.D.
Deputy State Epidemiologist
Oregon Health Division
1400 SW 5th Avenue
Portland, OR 97201
Texas Department of Health
1100 West 49th Street
Austin, TX 78756
|Utah||David J. Thurman, M.D., M.P.H.
Bureau of Epidemiology
Utah Department of Health
P.O. Box 16660
Salt Lake City, UT 84116-0660
|30 (Less than or equal to 18 years of age)
20 (Greater than 18 years of age)
|Wisconsin||Larry Hanrahan, M.S.
Wisconsin Department of Health and Social Services
One W. Wilson Street, Box 309
Madison, WI 53701
|* Questions regarding these reporting requirements should be directed to the contact person in each State. [Return to top of table]|
Workers should receive training [29 CFR 1926.21] that includes the following:
- Information about the potential adverse health effects of lead exposure
- Information about the early recognition of lead intoxication
- Information in material safety data sheets for new paints or coatings that contain lead or other hazardous materials [29 CFR 1926.59]
- Instruction about heeding signs that mark the boundaries of lead-contaminated work areas
- Discussion of the importance of personal hygiene practices in reducing lead exposure
- Instruction about the use and care of appropriate protective equipment (including protective clothing and respiratory protection)
- Information about specific work practices for working safely with lead-containing paints
Alan Echt, Phillip Froehlich, William Heitbrink, Leroy Mickelsen, Michael Montopoli, and Aaron Sussell were the principal contributors to this Alert. Comments, questions, or requests for additional information should be directed to these NIOSH investigators as follows:
For medical information, please contact
Paul Seligman, M.D., M.P.H.
Telephone: (513) 841-4353
Division of Surveillance, Hazard Evaluations, and Field Studies (DSHEFS)
For industrial hygiene information, please contact
Alan Echt, C.I.H., DSHEFS
Aaron Sussell, M.P.H., DSHEFS
Telephone: (513) 841-4374
For engineering information, please contact
William Heitbrink, Ph.D., C.I.H.
Leroy Mickelsen, M.S.
Telephone: (513) 841-4221
Division of Physical Sciences and Engineering (DPSE)
J. Donald Millar, M.D., D.T.P.H. (Lond.)
Assistant Surgeon General
Director, National Institute for Occupational Safety and Health
Centers for Disease Control
* For the purposes of this document, NIOSH has defined lead poisoning as a concentration of lead in whole blood (known by OSHA as blood lead level, or BLL) exceeding 50 micrograms per deciliter (µg/dl). See Table 4 for a list of actions required by the Occupational Safety and Health Administration (OSHA) general industry standard for various BLLs. [Return to main text]
** Code of Federal Regulations. See CFR in references. [Return to main text]
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30 CFR 11. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.
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