Lead


Problem:

Workers that repair or replace defective vessel parts may face hazards from lead.

Risk Description:

Exposure to lead can cause a variety of health problems. Although it has systemic effects throughout the body, some of the most dangerous outcomes are neurological. In adults, overexposure to lead can cause memory loss, headache, irritability, cognitive dysfunction, kidney damage, joint pain, and digestive issues. The International Agency for Research on Cancer (IARC) has described inorganic lead compounds as “probably carcinogenic to humans,” (WHO, 2006). Lead can enter the body by inhalation, skin contact, or by mouth.    

Sources of lead exposure in the construction industry include demolition, bridge maintenance, grinding, cutting, and welding on surfaces containing lead paint. Lead is a common component of many building materials, and lead alloy can be used to solder pipe joints, as a component of ductwork, and in electrical fittings and conduits. Although lead paint was banned for residential use in 1978, it is still legal to use on bridges and other industrial structures. Painters, plumbers, and welders are some of the construction workers most commonly exposed to lead.  

Although lead is hazardous to people of all ages, it is especially dangerous to children and women who are or may become pregnant. Lead’s neurological effects are most pronounced in children under 6, who absorb 4-5 times more lead than adults (WHO, 2017). Relatively low levels in children can cause stomach pain, headaches, developmental delays, behavioral problems, and seizures. Lead exposure in pregnant women has also been associated with miscarriage, stillbirth, and mental retardation. Lead can cause infertility in both men and women. Although lead is distributed to all parts of the body, it is stored long-term in the bones and teeth. It can then be re-released back into the bloodstream as a person ages, when they become pregnant, or when they fracture a bone.     

It is estimated that about 838,000 construction workers in the United States come into contact with lead on the job (OSHA, 2017). Research indicates that children living in these households have blood lead levels about three times as high as children in the general population (Roscoe et al, 1999). This is most likely due to workers unintentionally bringing home lead dust on their clothing. 


Level of Risk:

The risk of exposure to lead varies depending on a worker’s trade and the tasks they perform during their shift. Although the Occupational Safety and Health Administration’s (OSHA) Permissible Exposure Limit (PEL) in the construction industry is 50 µg/m3, workers are regularly exposed to airborne concentrations that exceed this limit.

Table 1: Common airborne lead levels during specific construction tasks.

50 to 500 µg/m3

500 µg/m3 to 2,500 µg/m3

>2,500 µg/m3

Manual demolition

Using lead-containing mortar

Abrasive blasting

Dry manual scraping

Lead burning

Welding

Dry manual sanding

Rivet busting

Torch cutting

Heat gun use

Power tool cleaning without dust collection systems

Torch burning

Power tool cleaning with dust collection systems

Cleanup of dry expendable abrasive blasting jobs

 

Spray painting with lead-based paint (LBP)

Abrasive blasting enclosure movement and removal

 

 


 

 

 

 

 

 

 

 

 

 

 

 

 

Source: OSHA Technical Manual, Chapter 3.

Studies have not yet established the exact relationship between airborne lead dust concentrations and levels of lead in the blood (commonly measured in µg of lead per deciliter of blood, or µg/dL), but 95% of reported elevated BLLs are work-related (CDC, 2009). Before 2015, an elevated blood lead level (BLL) was defined as 10 µg/dL or higher. In 2015, the National Institute for Occupational Safety and Health (NIOSH) recognized that this was not protective enough and lowered the reference level to 5 µg/dL. 

However, studies have shown that health risks exist even below 5 µg/dL. An increase in death from cardiovascular causes, such as stroke or heart attack, was demonstrated at levels as low as 2 µg/dL (Menke et al, 2006). In elderly populations, BLLs below 10 µg/dL but higher than 0 µg/dL were tied to poor performance on neurobehavioral tests (ATSDR, 2007).

Studies of workers in the construction industry show a high level of variability in BLLs depending on the worker’s trade and primary task. Workers involved in lead-based paint removal were shown to have a mean BLL of 18 µg/dL, while workers doing welding, brazing, soldering, or thermal cutting had a mean BLL of 24 µg/dL (Koh et al, 2015).

The following table shows the mean BLL observed in members of five different construction trades.

Table 2: Mean BLL by Trade.

Trade

Mean BLL, µg/dL

Laborers

7.6

Painters

5.9

Ironworkers

5.2

Plumbers

4.4

Electricians

2.4

Source: Koh et al, 2015.

This contrasts sharply with the mean BLL of .84 µg/dL among Americans between 2013-2014 (Tsoi et al, 2016). In fact, airborne concentrations of lead in construction are the highest of any other industry (Henn, 2011), and although exposure to lead has decreased over time for general industry, the same has not held true for construction (Okun, 2004).

Agency for Toxic Substances and Disease Registry (ATSDR). (2007). Draft toxicological profile for lead. Retrieved from https://www.atsdr.cdc.gov/toxprofiles/tp13.pdf

Centers for Disease Control (CDC). (2009). Adult blood lead epidemiology and surveillance - United States, 2005-2007. Morbidity and mortality weekly report (MMWR), 58(14): 365-369.

Henn, SA., Sussell, AL., Li, J., Shire, JD., Alarcon, WA. & Tak, S. (2011). Characterization of lead in US workplaces using data from OSHA's integrated management information system. American Journal of Industrial Medicine, 54: 356–365.

Koh, DH., Locke, SJ., Chen, YC., Purdue, M P. & Friesen, MC. (2015). Lead exposure in US worksites: A literature review and development of an occupational lead exposure database from the published literature. American Journal of Industrial Medicine, 58(6): 605–616.

Menke, A., Muntner, P., Batuman, V., Silbergeld, EK. & Guallar, E. (2006). Blood lead below 0.48 µmol/L (10 µg/dL) and mortality among US adults. Circulation, 114: 1388-1394.

Okun, A., Cooper, G., Bailer, AJ., Bena, J. & Stayner, L. (2004). Trends in occupational lead exposure since the 1978 OSHA lead standard. American Journal of Industrial Medicine, 45: 558–572.

Tsoi, MF., Cheung, CL., Tsang Cheung, T. & Cheung, BMY. (2016). Continual decrease in blood lead level in Americans: United States National Health Nutrition and Examination Survey 1999-2014. The American Journal of Medicine, 129(11): 1213-1218.


Assessment Info:

Working in demolition, bridge renovation, residential remodeling, or any other area where paint is scraped, sprayed, sanded, or blasted, raises the risk of being exposed to unsafe levels of lead. Performing hot work such as welding, brazing, soldering, or thermal cutting on surfaces that may have been coated in lead paint can release large quantities of lead fumes. Lead can also be present in solder, mortar, tank linings, batteries, and glazes. If you are not sure if the substance you are working with contains lead, consult the Safety Data Sheet (SDS). However, it is important to keep in mind that SDS are not always 100% accurate, and may not exist when performing remodeling or demolition work.

Lead dust and fumes do not have a distinctive smell, so personal air monitoring is necessary if workers suspect they may have airborne exposures. A pump and filter can be attached to a worker’s clothing during their shift, and an accredited lab will analyze it for lead content. Settled lead dust can also be sampled using a wipe sample, which measures the amount of lead on a horizontal surface. Sampling should always be done under the supervision of a professional industrial hygienist. 

Your doctor can also draw blood to measure the amount of lead already in your body. However, blood lead levels are not a good representation of chronic lead exposure because lead does not stay in the bloodstream long-term. About 94% of the lead in an adult human’s body is kept in the bones and teeth. Stress, aging, and some health conditions cause stored lead to reenter the bloodstream (ATSDR, 2017). Keep in mind that BLLs measure lead exposure from all sources, including lead you may have been exposed to in your home.   


Regulations & Standards:

The current OSHA PEL for lead in construction is 50 µg/m3, averaged over an 8-hour period. OSHA also has an Action Level (AL) of 30 µg/m3, which triggers air monitoring, training, and medical surveillance requirements. OSHA requires that employees with a BLL at or above 50 µg/dL be removed from work if certain conditions are met. However, it is important to note that BLLs significantly lower than 50 µg/dL are associated with neurological problems, organ damage, and cancer. 

Federal OSHA Standards are enforced by the U.S. Department of Labor in 26 states. There are currently 22 states and jurisdictions operating complete State plans (covering both the private sector and state and local government employees) and 5 - Connecticut, Illinois, New Jersey, New York and the Virgin Islands - which cover public employees only. If you are working in one of those states or jurisdictions you should ensure that you are complying with their requirements.

Regulations adopted by a state must be at least as protective as the corresponding federal standard. Work may also be subject to rules of other federal, state and local agencies. Even where there is no hazard specific standard, OSHA provides a general duty for the employer to provide a work site free from recognized hazards.