Worker Health Study Summaries
Research on long-term exposure
Lead Smelters (2) (Lead Exposure)
NIOSH made a study of lead exposure.
Why was the study done?
We know that people who work with lead have an increased chance of getting sick. Lead dust can stick to people’s hands, clothing, food, and cigarettes.
A person can breathe in or swallow the dust. If a person takes in too much lead, he or she can get sick from lead poisoning.
This fact sheet has results from a study on lead that we just finished. This study focused on whether workers exposed to lead at a lead smelter showed increased death from kidney disease, kidney cancer, and strokes.
Who was in the study?
1,990 male workers, who worked at a lead smelter between 1940 and 1965, were in the study.
Of greatest interest were workers from the high-lead departments including the sinter plant; materials recovery; charge preparation; the silver, lead, and cadmium refineries; the blast furnace; and the slag fuming furnace. Men from other departments were also in the study.
The study was based entirely on records. Workers did not have medical exams.
We looked at employee work histories and death certificates. We wanted to know where people worked and if they were still living. If they had died, we wanted to know what they died from.
Remember, the findings do not mean that you have these illnesses now, or will necessarily get them in the future.
The findings mean that, as a group, employees who worked with lead, may be at greater risk for illness or death from certain diseases.
Kidney Disease (Not Cancer):
The NIOSH study suggests that the risk of dying from kidney disease was highest for people exposed to lead for more than 20 years (4 found; 1 expected).
We think that the risk of dying from kidney disease was mainly for workers hired before the 1960s when lead exposures (and possibly cadmium) were much higher.
What can you do about kidney disease?
Tell your doctor that you worked with lead. This information should be in your medical records. Your doctor can do tests to check for kidney problems.
High blood pressure and kidney disease are related. So, keeping your blood pressure under control is important.
You can do this by:
- losing body-weight
- decreasing salt and alcohol
- exercising regularly
- taking blood-pressure drugs (if given by a doctor)
An earlier study showed that animals exposed to high levels of lead were more likely to get kidney cancer. Our study shows that people exposed to lead might be at risk for kidney cancer too.
Lead smelter employees as a group did have a slightly higher risk for getting kidney cancer (9 kidney cancer deaths found; 5 expected).
For those employees who worked in the high-lead departments, there also was a higher risk (8 cases of kidney cancer occurred; only 3 expected).
What can you do about kidney cancer?
Seeing blood in your urine may be a sign of a problem. It is very important to tell your doctor if this happens to you .
The NIOSH study found that compared to the U.S. population, the chance of having a stroke was slightly increased (26 deaths found; 18 expected).
There was evidence that the longer one’s exposure (greater than 20 years), the more risk there was.
What can you do about stroke?
There are some steps that you can take to protect yourself against having a stroke:
- Tell your doctor your work history
- Control your blood pressure
- Stop smoking
- Stay at a healthy weight
- Decrease cholesterol in diet
- Exercise regularly
- Limit your alcohol intake
- Keep diabetes under control.
We found more deaths from lung disease than expected (40 found, 21 expected). At least 8 were due to silicosis, which comes from breathing silica.
Although there was silica in some areas of the smelter, we think the deaths from lung disease were not due to the smelter.
Many of the workers dying of lung disease also worked in the underground mines. These mines had high levels of silica.
We believe that the deaths could be due to underground mining.
What can you do about lung disease?
If you are having breathing problems, tell your doctor about your work history. Your doctor can check your lungs with a simple breathing test.
Quitting smoking is important for healthy lungs.
Message for Study Participants
This NIOSH study of lead smelter employees helped us learn more about the possible hazards of exposure to lead.
You may want to speak to your doctor about the information in this fact sheet
Also, it would be a good idea to send a copy of this information to your doctor to update your medical file.
If you have questions about this study or have other questions about lead, please call the NIOSH toll-free number: 800-356-4674.
Selevan S, Landrigan P, Stern F, et al. (1985). Mortality of lead smelter workers. American Journal of Epidemiology 122 (4): 673 -683.
Steenland K, Selevan S, Landrigan P (1992). Mortality of lead smelter workers: An update. American Journal of Public Health 82(12): 1641-1644.