Lead is a cumulative and persistent toxic substance that poses a serious health risk. It is a naturally occurring element found in small amounts in the earth’s crust. While lead does have some beneficial uses, it can be toxic to humans and animals, causing health effects. Pure lead (Pb) is a heavy metal at room temperature and pressure. A basic chemical element, it can combine with various other substances to form numerous lead compounds. Below is a description of the characteristics, uses, and Permissible Exposure Limit (PEL), and Action Level (AL) for lead:
Click on the button below to see a video giving you an overview lead and its health effects.
We encourage you to visit the NIOSH Pocket Guide to Chemical Hazards - Lead webpage that contains chemical and physical properties and other information on lead.
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Although the focus of the course is on employees working in shipyards, it's important to understand that lead hazards can also affect each employee's family. With that in mind, we'll cover the effects of lead exposure on children as well as adults.
Lead is particularly dangerous to children because their growing bodies absorb more lead than adults do and their brains and nervous systems are more sensitive to the damaging effects of lead. Babies and young children can also be more highly exposed to lead because they often put their hands and other objects that can have lead from dust or soil on them into their mouths. Children may also be exposed to lead by eating and drinking food or water containing lead or from dishes or glasses that contain lead, inhaling lead dust from lead-based paint or lead-contaminated soil or from playing with toys with lead paint. See more information this topic.
Adults may be exposed to lead by eating and drinking food or water containing lead or from dishes or glasses that contain lead. They may also breath lead dust by spending time in areas where lead-based paint is deteriorating, and during renovation or repair work that disturbs painted surfaces in older homes and buildings. Working in a job or engaging in hobbies where lead is used, such as making stained glass, can increase exposure as can certain folk remedies containing lead. A pregnant woman’s exposure to lead from these sources is of particular concern because it can result in exposure to her developing baby.
Click the button below to learn more about the hazards of lead exposure at home.
Shipyard operations, such as sandblasting and shipbreaking, also called ship scrapping, ship disposal, or ship recycling, can result in exposure to lead. Lead is commonly used in maritime paints as an anticorrosive agent. It is also used in greases, as tetraethyl lead added in fuels, and as radiation shielding in nuclear-powered vessels and submarines.
Lead exposure also has many sources in general industry and construction, both on and off the job. Exposure to lead may occur from numerous sources, including:
Then click on the buttons below to see videos on lead exposure at a gun range and exposure from recycling lead batteries.
Shipyard employees who engage in abrasive blasting are most commonly at an increased risk of exposure to toxic lead dust. Helpers (e.g., the "pot tender" and cleanup personnel) and others may also be at risk if they work in the vicinity of areas where abrasive blasting is conducted.
Potential exposure to dust and air contaminants is the primary health hazard associated with abrasive blasting. Abrasive blasting can generate large quantities of dust that can contain high levels of toxic air contaminants. The source of the air contaminants includes the base material being blasted, the surface coating(s) being removed, the abrasive being used, and any abrasive contamination from previous blasting operations. This means that employees can have exposures to multiple air contaminants from both the abrasive and the surface being blasted. Potential sources of lead dust that might be associated with abrasive blasting in shipyards and their sources are:
Click on the button below to learn more about the hazards of lead exposure in various workplaces.
Lead poisoning usually occurs over a period of months or years. It can cause severe mental and physical impairment. Shipyard work is traditionally hazardous, with an injury-accident rate more than twice that of construction and general industry.
The lead exposure pathway has five components:
A Shipyard, located in Wisconsin, was fined approximately $1.4 million in penalties for multiple lead-related safety and health violations. Fraser Shipyards accepted a contract with low profit margins and penalties for schedule delays.
In their push to get the project done on time, the employer failed to:
OSHA determined Fraser Shipyards' management knew lead was present throughout the vessel, which was originally built in 1959.
When the company tested their 134 employees, 75 percent of those tested had elevated blood lead levels. Fourteen employees had lead levels up to 20 times the exposure limit.
Overexposure to lead can lead to brain damage, gastrointestinal harm, anemia, and kidney disease.
Source: DOL News Release (August 2016)
There is no sharp dividing line between rapidly developing acute effects of lead, and chronic effects which 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.
Chronic long-term overexposure to lead can cause peripheral muscle weakness, pain, and paralysis of extremities, disruption of hemoglobin synthesis and anemia, loss of kidney function, increased blood pressure, kidney disease, reduced sperm count and male sterility, and increase the risk of cancer.
Respiratory illness caused by fume and smoke inhalation and exposure to heavy metals, such as lead, are of particular concern in shipyard workers. Excess cancer morbidity has been detected in several groups of shipyard workers, especially cancers of the respiratory system, with welders appearing to be at particular risk.
Click the button to watch a video on lead exposure at a battery recycling plant.
Exposure to lead and lead chemicals can occur through ingestion, inhalation, dermal absorption, and trans-placental (endogenous) routes.
The two primary entry routes into the body for lead are ingestion (eating) and inhalation (breathing). Lead (except for certain organic lead compounds not covered by the standard, such as tetraethyl lead) is not absorbed through your skin.
When lead is scattered in the air as a dust, fume or mist it can be inhaled and absorbed through your lungs and upper respiratory tract. Inhalation of airborne lead is generally the most important source of occupational lead absorption. You can also absorb lead through your digestive system if you handle contaminated items or handle them with hands contaminated with lead.
Click on the buttons below for more information on each of these exposure routes.
Lead exposure in the general population (including children) occurs primarily through ingestion, making it the route that most commonly leads to elevated blood lead levels (BLLs). This includes swallowing a foreign body containing lead (i.e., jewelry, etc.).
From 20% to 70% of ingested lead is absorbed into the body, (with children generally absorbing a higher percentage than adults).
Inhalation is the second major pathway of exposure for the general population in the United States. The amount absorbed from the respiratory system depends on particle size, respiratory volume, amount of deposition, and the mucociliary clearance of the inhaled lead.
Dermal exposure plays a role for exposure to organic lead among workers, but is not considered a significant pathway for the general population.
Endogenous exposure to lead may contribute significantly to an individual's current BLL. Numerous reports document lead poisoning resulting from retained bullet or shrapnel fragments; thus, a history of military or other penetrating trauma may be important. If in a pregnant woman, this poses a particular risk to the developing fetus. Trans-placental exposure to the unborn child can happen if the mother is exposed to lead.
Click on the button below to learn why lead is so bad for humans.
A significant portion of the lead that you inhale or ingest gets into your blood stream. Once in your blood stream, lead circulates throughout your body and is either filtered out of the body or stored in various organs and body tissues. As exposure to lead continues, the amount stored in your body will increase. Even though you may not be aware of any immediate symptoms of disease, stored lead can be slowly causing irreversible damage to cells, organs, and body systems.
Click on the button below to see the list of symptoms of chronic overexposure to lead.
Symptoms of Chronic Exposure to Lead
Encephalopathy. Damage to the central nervous system in general and the brain (encephalopathy) in particular is one of the most severe forms of lead poisoning. The most severe, often fatal, form of encephalopathy may be preceded by vomiting, a feeling of dullness progressing to drowsiness and stupor, poor memory, restlessness, irritability, tremor, and convulsions. It may arise suddenly with the onset of seizures, followed by coma, and death.
Peripheral neuropathy. There is also a tendency for muscular weakness to develop. This weakness may progress to paralysis often observed as a characteristic "wrist drop" or "foot drop" and is a manifestation of a disease to the nervous system called peripheral neuropathy.
Kidney disease. Chronic overexposure to lead also results in kidney disease with few, if any, symptoms appearing until extensive and most likely permanent kidney damage has occurred. When overt symptoms of urinary dysfunction arise, it is often too late to correct or prevent worsening conditions, and progression to kidney dialysis or death is possible.
Reproductive systems. Chronic overexposure to lead impairs the reproductive systems of both men and women. Overexposure to lead may result in decreased sex drive, impotence and sterility in men. Lead can alter the structure of sperm cells raising the risk of birth defects. There is evidence of miscarriage and stillbirth in women whose husbands were exposed to lead or who were exposed to lead themselves. Lead exposure also may result in decreased fertility, and abnormal menstrual cycles in women.
Anemia. Overexposure to lead also disrupts the blood-forming system resulting in decreased hemoglobin (the substance in the blood that carries oxygen to the cells) and ultimately anemia. Anemia is characterized by weakness, pallor and fatigue as a result of decreased oxygen carrying capacity in the blood.
Each employee is responsible for reporting signs and symptoms of health problems. You should immediately notify your employer if you develop signs or symptoms associated with lead poisoning or if you desire medical advice concerning the effects of current or past exposure to lead on your ability to have a healthy child. You should also notify your employer if you have difficulty breathing during a respirator fit test or while wearing a respirator. In each of these cases your employer must make available to you appropriate medical examinations or consultations. These must be provided at no cost to you and at a reasonable time and place.
Measuring your blood lead level is the most useful indicator of the amount of lead being absorbed by your body. Although there is NO established absolutely safe level of lead exposure, the best way to prevent all forms of short-term and long-term lead-related impairments and diseases is to maintain the level of lead in your blood below 40 micrograms of lead per 100 grams of blood (40ug/100g). Once your blood lead level climbs above 40ug/100g, your risk of disease increases.
Lead is toxic to both male and female reproductive systems. Lead can alter the structure of sperm cells and there is evidence of miscarriage and stillbirth in women exposed to lead or whose partners have been exposed. Children born to parents who were exposed to excess lead levels are more likely to have birth defects, mental retardation, or behavioral disorders or to die during the first year of childhood.
Workers who desire medical advice about reproductive issues related to lead should contact qualified medical personnel to arrange for a job evaluation and medical followup--particularly if they are pregnant or actively seeking to have a child. Employers whose employees may be exposed to lead and who have been contacted by employees with concerns about reproductive issues must make medical examinations and consultations available.
Under certain limited circumstances, a physician may prescribe special drugs called chelating agents to reduce the amount of lead absorbed in body tissues. Using chelation as a preventive measure to lower blood level, but continue to expose a worker, is prohibited. The therapeutic or diagnostic chelations of lead that are required must be done under the supervision of a licensed physician in a clinical setting. The employee must be notified in writing before treatment of potential consequences and allowed to obtain a second opinion.
Click on the button below to learn about preventive measures.
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