Protecting Workers Exposed to Lead-based Paint Hazards
A Report to Congress
DHHS (NIOSH) PUBLICATION NO. 98-112
JANUARY 1997
Chapter 2
NIOSH SURVEILLANCE, INTERVENTIONS, AND EVALUATIONS
Introduction
The Adult Blood Lead Epidemiology and Surveillance Program (ABLES)
NIOSH conducts surveillance, interventions, and health hazard evaluations (HHEs) to identify and reduce occupational lead exposures. Surveillance of adult BLLs has allowed NIOSH and other health agencies to identify high-risk workplaces, and to disseminate data for planning, implementing, and evaluating occupational lead poisoning prevention programs and interventions. In this context, intervention refers to activities designed to reduce the frequency of worker lead poisoning or elevated BLLs 1,2. NIOSH HHEs provide another way to assess occupational exposures in the workplace and identify new and emerging hazards. The recent increase in lead abatement and lead-based paint (LBP) removal activities has created new hazardous circumstances for workers.
THE ADULT BLOOD LEAD EPIDEMIOLOGY AND SURVEILLANCE PROGRAM (ABLES)
The NIOSH ABLES program was started in the late 1980s by NIOSH investigators working with health departments in several states, including California, New Jersey, New York, and Texas. The objective of the ABLES program is to assist states in establishing surveillance systems for laboratory-based reporting of adult elevated BLLs, which are usually caused by occupational exposures. Standardized reporting to the NIOSH national surveillance database began in 1992. Since then, the numbers of participating states have increased each year3.
NIOSH is currently working with 35 states which collect and disseminate information on adult BLLs. Twenty-seven states contribute data to the national adult blood lead data maintained and reported by NIOSH. In addition, eight states are developing ABLES programs (Figure 2.1 and Appendix A). The states which provide data to NIOSH have regulations that specify a reportable BLL for adults (see Appendix A for reporting levels) and require laboratories to report BLLs to appropriate state agencies. Twenty-one of the 27 states had ABLES programs supported by NIOSH cooperative agreements in 1997 (Alabama, Arizona, Connecticut, Iowa, Massachusetts, Maryland, Michigan, Minnesota, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Texas, Washington, Wisconsin, and Wyoming).
NIOSH reports ABLES data on a quarterly basis in the Morbidity and Mortality Weekly Report (MMWR), a weekly publication of the Centers for Disease Control and Prevention.
In 1995, 23 states reported 12,664 adults with elevated BLLs greater than or equal to 25 µg/dL4. These 23 states represented 64 percent of the U.S. population (U.S. Bureau of the Census, 1993).
The ABLES data may represent only the tip of the iceberg with respect to the extent of occupational lead exposure in the United States. The Third National Health and Nutrition Examination Survey, NHANES III (1988–1991), estimated that as many as 700,000 adults (20 to 74 years of age) may have elevated BLLs greater than or equal to 25 µg/dL5.
Investigations by NIOSH and others suggest that one of the most important factors contributing to the large disparity between the NHANES III estimate and the actual numbers of persons with elevated BLLs reported to ABLES is infrequent medical monitoring by employers, especially in the construction industry. Studies conducted before the OSHA construction lead standard took effect in 1993 found a lack of lead exposure assessment, periodic medical monitoring, or both, among residential and industrial painting and lead abatement contractors6,7,8. However, a recent analysis of surveillance data by the California Department of Health Services suggests that the vast majority of construction companies still do not test employees' BLLs, even though this is required by law9. Similarly, an OSHA analysis of inspection data for a recent one-year period (October 1994 through September 1995) found that the most frequently violated OSHA standard in standard industrial classification (SIC) codes 1622 (bridge, tunnel, and elevated highway contractors), 1721 (painting and paper hanging), and 1795 (wrecking and demolition) was the construction lead standard (29 CFR 1926.62). Another factor is nonoccupational exposures. In one NIOSH study (described in Chapter 2, State-based Research—Overview), nonoccupational exposures were responsible for approximately 14 percent of persons with BLLs greater than or equal to 40 µg/dL.
Figure 2.1 States Participating in NIOSH Adult Blood Lead Epidemiology and Surveillance (ABLES) Program, 1997
ABLES states funded by NIOSH have protocols for investigating reported elevated BLL cases and mechanisms for linking elevated BLL case reports with follow-up activities. NIOSH currently provides about $25,000 to $30,000 per year to 16 states to assist in conducting surveillance and intervention activities. Resource constraints require the states to prioritize their intervention efforts.
Intervention capacity varies considerably among the ABLES states. Several states, including California, Connecticut, New Jersey, Massachusetts, and Washington, are good models for identifying high-risk industries and responding with interventions. These states have developed educational materials for workers and employers in high-risk industries. More elaborate state intervention activities include interviews with the workers' physicians and workplace follow-up visits. Employers may be contacted to determine if the employer is aware of regulatory requirements to protect workers from occupational lead poisoning. Intervention includes technical consultation for employees, employers, and physicians and educational outreach through workshops and printed materials. In the worst circumstances (e.g., an employer fails to correct problems resulting in elevated BLLs), the case may be referred to the OSHA consultation or compliance programs. States with minimal intervention resources typically limit their follow-up activity to contacting only those workers with the highest BLLs, usually greater than or equal to 50 µg/dL, to provide information and medical referrals.
In 1993, NIOSH-supported research projects began in Illinois, Washington, Connecticut, and New Jersey. These projects targeted workers exposed to lead in the construction industry. Findings from these projects are discussed in the next section. The New Jersey study regarding take-home lead exposures is discussed in Chapter 3. In 1994, a NIOSH-funded intervention project for preventing lead poisoning among residential and commercial painters started in California. Preliminary results are reported in the next section. In 1995, NIOSH-funded research projects were begun in Washington and Iowa to develop model interventions to prevent occupational lead poisoning. These ongoing projects are expected to produce intervention models that will be applicable to general industry and construction.
Information on the source of lead exposure is not currently available in the national ABLES database maintained by NIOSH. However, in 1991, due in part to the reports of lead poisoning among bridge workers from several states, NIOSH published and distributed nationally a NIOSH Alert to prevent lead poisoning in construction workers10. Since the ABLES program was begun, NIOSH, in collaboration with the CDC's National Center for Health Statistics, has held several workshops for state personnel regarding appropriate techniques and data sources for coding the industry and the occupation of persons with elevated BLLs reported to ABLES registries. This information will eventually allow NIOSH to routinely identify high-risk occupations for lead poisoning.
The utility of this type of information is illustrated by a 1994 Massachusetts study. From 1991 to1993, 1,320 individuals, age 15 or older, with BLLs greater than or equal to 25 µg/dL, were reported to the Massachusetts Occupational Lead Registry11. State investigators followed up on the 381 registrants (29%) with BLLs greater than or equal to 40 µg/dL. An exposure source was determined for 362 people, and 313 (86%) were found to be occupationally exposed to lead. Of those occupationally exposed, 196 (63%) were employed in the construction industry, primarily as residential or industrial deleaders [Massachusetts deleading regulations require blood lead monitoring of workers employed as deleaders.] and bridge or house painters. Of the 49 workers with BLLs greater than or equal to 60 µg/dL, 39 (80%) were construction workers, and painters comprised approximately one-half of that group.
Among the other 49 registrants with BLLs greater than or equal to 40 µg/dL who had nonwork lead exposures, the primary sources were shooting at firing ranges and renovation and repair of their own homes.
State-Based Research Projects—Progress and Results to Date
The primary goals of the project were to identify residential painting contractors and to assess lead exposures and worker protection at typical job sites12. The grantee, the Safety and Health Assessment and Research for Prevention (SHARP) program, is a part of the Washington State Department of Labor and Industries, which is the sole provider of workers' compensation insurance in Washington State.
SHARP initially identified 597 painting contractors in the two most populated counties (King and Pierce) with SIC code 1721 (painting and paper hanging) and a similar risk classification in the State's workers' compensation insurance database. The contractors were mostly very small businesses; 50 percent had fewer than one full-time equivalent (FTE) employee, 73 percent had five or fewer, and 82 percent had fewer than 10.
Eighty-eight contractors were contacted for a telephone survey, 61 (69%) of which agreed to participate. The contractors surveyed estimated that, on average, they spent 15 percent of their time in pre-1950 homes, 18 percent of their time in 1950–1977 homes, and 68 percent of their time in 1978 and newer homes. The contractors reported using the following high-risk surface preparation methods frequently or occasionally (percent): power sanding/grinding (51%), chemical stripping (35%), and heat gun (15%).
SHARP conducted five site visits at pre-1950 single-family homes to assess employee lead exposures during surface preparation work. Exposures for nine painters were measured, four of whom (44%) were overexposed to lead on the days of the survey (see Table 2.1). The hazardous exposures were during power sanding/grinding (range: 100 to 2142 µg/m3) and hand scraping (108 µg/m3).
Table 2.1 Worker Lead Exposures During Surface Preparation for Residential Painting *
| House number | Task | Worker number |
Lead exposure 8-hr TWA (ug/m3) |
Paint lead concentration (%)** |
|---|---|---|---|---|
| 1 | Power sanding/grinding | 1 2 |
2142 1007 |
5-17 |
| 2 | Hand scraping | 3 4 |
108 31 |
1.2-3.3 |
| 3 | Hand scraping/painting | 5 6 |
4.1 1.2 |
5.7 |
| 4 | Hand scraping/sanding | 7 8 |
1.2 0.4*** |
<0.001 |
| 5 | Power sanding/grinding | 9 | 100 | <0.001 |
SHARP concluded that painters have hazardous LBP exposures, use of personal protective equipment and hygiene practices were often inadequate, and painters may increase surface lead contamination in residences. The results were consistent with other research, which has found little correlation between paint lead concentrations and workers' health risk (see "Occupational Exposure Assessment" in Chapter 4).
Eight of the nine painters agreed to participate in BLL monitoring; and all had relatively low BLLs (range: 2 to 18 µg/dL). These workers were probably protected primarily by the relatively low frequency with which they performed high-risk work. All reported spending no more than one-half their time in pre-1950 homes, and only occasionally using the hazardous power sanding/grinding method.
The goal of this project, conducted by the Occupational Health Surveillance Program of the Connecticut Department of Public Health and Addiction Services, was to monitor the effectiveness of health and safety specifications in state contracts for bridge repainting13. After an interstate highway over the Mianus River collapsed in 1983, Connecticut began an intensive bridge repair program. In 1992, the Connecticut Department of Transportation implemented specifications in all contracts for bridge painting that required contractors to have approved programs to protect workers from lead poisoning (see summary in Appendix B).
The investigators used two methods for evaluating the effectiveness contract specifications in reducing worker lead exposures: comparison of data from Connecticut bridge sites before and after the contract specifications took effect, and a prospective study of worker lead exposures at a large bridge painting job.
Evaluations at five bridge painting sites, conducted in 1990, were compared to similar evaluations of two bridge sites in 1994. The investigators found marked improvements in the contractors' safety and health programs at selected Connecticut bridge sites between 1990 and 1994 (Table 2.2). This is consistent with BLL data collected throughout the state as part of the NIOSH-supported Connecticut Road Industry Surveillance Project (CRISP), which was begun in 1990. CRISP investigators found that from 1991 to 1994 average BLLs declined from 42 µg/dL to 17 µg/dL for blasters/painters, and from 21 µg/dL to 11 µg/dL for iron workers/welders14. These improvements may be the result of the medical surveillance of bridge workers under CRISP and the Connecticut Department of Transportation's contract specifications for worker protection. Two other changes, which took place on the national level, may also have affected the contractors' attention to worker protection: a NIOSH Alert documenting construction lead hazards was published in 1991 and the federal OSHA construction lead standard took effect in 1993.
NOTES:
‡ Respirators were either PAPRs or half-face negative pressure for all tasks except blasting, where Lancer blast helmets were used.
The prospective evaluation at one bridge painting site over a period of four months demonstrated that, even with health and safety contract specifications, bridge workers were still routinely exposed to high levels of lead. Average worker lead exposures were well above the OSHA PEL. However, the contractor's health and safety program (including personal protective equipment) was successful in preventing the most severe exposures: no worker's BLL reached 50 µg/dL. On the other hand, 10 of 46 participating workers (22%) had at least one elevated BLL > 25 µg/dL during the study, and 19 workers (41%) had BLL increases of 10 µg/dL during the study (Table 2.3).
Table 2.3 Airborne Lead Exposures and BLLs, Connecticut Prospective Bridge Site Study
The California Department of Health Services designed, implemented, and evaluated an intervention to improve lead poisoning worker protection among residential painting contractors who were potentially exposed to LBP hazards. The intervention included development of a comprehensive lead safety manual and training workers and contractors about lead-safe practices.
Twenty-two painting contractors with 134 employees were recruited for this study in 1994. Employers were interviewed about methods they used for surface preparation, and about their lead safety and health programs. Lead exposure assessments were conducted, and pre- and post- intervention biological monitoring and questionnaires were administered in 1994. A follow-up survey to assess retention of information about lead-safe practices was done in 1995.
Results indicated that the pre-intervention worker protection programs among the participating contractors were generally lacking and that contractors were poorly informed about the requirements of the OSHA construction lead standard. A substantial proportion (37 percent) of contractors did not test for the presence of lead at the work site. High-risk paint removal methods, including dry scraping, dry sanding, power sanding without local exhaust ventilation (LEV), open flame torch burning, and heat gun, were often used. The contractors rarely performed lead exposure assessment or medical monitoring—only one of the 22 painting contractors had ever assessed employee airborne lead exposures, and only two did routine BLL monitoring of employees. Many contractors indicated that they did not provide workers any lead safety training, the proper type of respirators or respiratory programs, or protective work clothing.
The exposure assessment, which included 11 of the 22 participating painting contractors, consisted of full-shift and task-based personal exposure monitoring, sampling of disturbed painted surfaces (all had LBP), and observation of work practices. A total of 25 full-shift employee exposures were measured, representing a mix of surface preparation activities and other daily tasks.
Fifty-four task-based exposure measurements were collected for these surface preparation tasks: power sanding with and without high-efficiency particulate air (HEPA) vacuum exhaust, manual dry sanding, wet sanding, dry scraping, open flame torch/scraping, heat gun/scraping. Hazardous exposures to LBP frequently occurred among the residential painters during surface preparation work. The mean full-shift exposure was 57 µg/m3 (range: 1 to 548 µg/m3), and 6 of the 25 full-shift exposures (24%) exceeded the OSHA PEL.
The results for the task-based worker exposures were categorized according to the paint lead concentration (see Table 2.4). On surfaces with low lead levels in paint (0% to 10% lead [Pb]), both power sanding without HEPA exhaust and dry scraping resulted in average exposures that were hazardous. On surfaces with medium paint lead levels (11% to 20% Pb), power sanding with or without HEPA vacuum exhaust, manual dry sanding, and dry scraping resulted in average exposures that were hazardous. Nonhazardous average lead exposures were measured for heat gun and open flame torch removal methods in this study, but larger studies have documented very high exposures for those methods (see Chapter 4).
1990 and 1994 Connecticut Bridge Studies
Job site characteristics
Historical
study, 1990Small bridges,
1994Comment
Respirators available
A*
A
Appropriate filters in use†
A
A
Appropriate respirators for
exposure‡N
U
Rigging was performed without
the use of respirators on one
occasion
Fit testing
N
A
Medical certification
N
A
Respirator storage &
maintenanceN
A
Wash-up facilities
N
A
Change area provided
N
A
Clothing storage—clean &
dirty separate§N
A
Work Practices#
N
U
Dry sweeping done occasionally
Hygiene practices**
N
U
Improper handwashing for some
workers
Employee training
N
A
Shower onsite or available
N
A
Clean/separate eating area
N
A
IH presence on site
N
A
Showers taken
N
U
Some workers did not take
complete showers
† The sections on respirator filters, fit-testing, storage and maintenance, and medical certification were judged by compliance with the OSHA construction lead standard.
§ Clothing storage required separate storage for clean and dirty clothing.
# Unacceptable work practices included sweeping, shoveling, and dumping blast residue, cleaning blaster helmets with high pressure air, and depositing respiratory equipment in lead-exposed areas.
** Unacceptable hygiene practices included eating, drinking, and smoking in lead-exposed areas and failure to wash hands prior to these activities.
Job Category
Mean air
lead
exposure
(ug/m3No. of
workersNo. with at
least one BLL
>25ug/dLNo. with
BLL
increase >
10ug/dLNo. with
BLL
decrease >
10ug/dL
Laborers/
groundsworkers73
23
3
9
4
Blasters/painters
2720
23
7
10
2
Totals
46
10
19
6
Surface preparation method
Average task-specific lead exposures (ug/m3) by percentage lead in paint * (number of air samples)
0-10% Pb †
11-20% Pb †
21-45% Pb †
Power sanding - without HEPA vacuum exhaust
97 (4) ‡
899 (6) ‡
Manual dry sanding
55 (3)
605 (6)
Dry scraping
24 (6)
94 (12)
Power sanding-with HEPA vacuum exhaust
23 (2) §
52 (2) #
26 (3)
Open flame torch and scraping **
8 (1)
10 (4)
Heat gun and scraping **
3 (3)
2 (3)
Wet sanding
3 (3)
* Air sample duration was 30 minutes unless otherwise noted.
† Average percentage by weight, mean of two bulk samples per surface.
‡ Sample duration for one sample was 20 min.
§ Sample duration for both samples was 10 min.
# Sample duration for both samples was 20 min.
** Paint was heated only to the softening point.
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