- What is Lead?
- Materials Suspected of Containing Lead
- How does Exposure Occur?
- Health Effects
- Exposure Limits
- Guidelines for Minimizing Exposures
- Tasks that Do Not Produce Excessive Exposures
- Tasks that May Produce Excessive Exposures
- Tasks that Do Produce Excessive Exposures
- Medical Considerations
- Waste Disposal Guidelines
- Information Web Sites
Poisoning as a result of overexposure to lead is the oldest recorded occupational disease. The significant health risk posed by too much lead entering the human body has been known and documented for thousands of years. Most lead exposure problems in adults occur from occupational exposures in the construction or manufacturing industries. An especially high health risk from excessive lead exposure exists for pregnant women and young children. Most recently, concerns about lead exposure have focused on the potential danger to young children from lead in and around homes, day care centers, and pre-schools.
What is Lead?
Lead is a soft, dense, inorganic heavy metal that oxidizes in air and is commonly found in the environment in a number of ores. Lead is often combined with other metals to form alloys and other substances to create a variety of compounds. Lead-based paint is paint that contains at least 1 mg/cm2 or 5000ug/g (0.5%) lead by weight.
Items and Materials Containing Lead
Items and materials that are commonly known to contain lead include:
- Any painted surface on the interior or exterior of a building or structure constructed prior to 1978.
- Debris, paint chips, or dusts inside or near the exterior of pre-1978 painted buildings and structures.
- Soil from or next to the exterior of pre-1978 painted buildings and structures.
- Lead pipes, lead based solder or plumbing fixtures in older buildings, and lead lined water coolers.
- Soil near heavily used streets and roads.
- Window glazing.
- Drinking water delivered through piping in older buildings.
- Old toys, imported toys.
- Lead-glazed and/or lead-painted pottery.
- Leaded crystal.
- Sinkers, ammunition, stain glass work.
- Storage batteries.
- Roof flashing.
- In resins as a stabilizer.
- As radioactive protective shielding.
- Telephone and television cable sheathing.
How does Exposure Occur?
Inhalation is the most common source of occupational lead exposure. Lead can become airborne when it is burned or melted to a temperature high enough to release a fume into the air. It is also released into the air when dust from lead painted surfaces is disturbed, or created by abrasion of the paint. Lead dust can also be released from contaminated clothing worn by a worker. Airborne lead dusts or fumes can be inhaled into the lungs and upper respiratory tract, where it is readily absorbed and distributed throughout the body.
Ingestion is the most common source of lead exposure in children. Small children may eat lead paint chips or play in contaminated soil. While adults do not typically eat paint chips, they may handle cigarettes, food, chewing tobacco, or apply make-up that has been contaminated by lead, or use these products with lead-contaminated hands. Lead can also be ingested from water that has been contaminated by lead in water pipes or containers.
Skin absorption is not normally a lead hazard because inorganic lead is not absorbed through the skin. Skin absorption was a hazard when skin absorbable organic leads (tetraethyl and tetramethyl lead) were used as gasoline additives; their use has been banned by the EPA since 1/1/1996.
The effects of lead normally accumulate over time from a series of exposures. Most lead is absorbed through the lungs or digestive tract and enters the blood stream. While some lead in the blood stream is excreted, the rest remains in the blood and is stored in other tissues. Extended exposure to lead, especially in high doses, increases the amount stored in the body. When too much lead has entered the body, visible effects and symptoms begin to appear. Lead poisoning is normally treatable, though some of the effects can be permanent when exposure levels have been excessive for long periods of time. Children under the age of six and fetuses exposed through lead in the mother’s blood are most susceptible to lead poisoning. Lead poisoning has been linked to anemia, central nervous system disorders, kidney and immune system damage, reproductive disorders, and learning disabilities.
In both adults and children, the signs and symptoms of lead poisoning are often confused with those of other common illnesses and misdiagnoses can easily occur. Because symptoms do not usually develop until the condition has become very serious, someone with lead poisoning may appear to be healthy.
Common signs and symptoms of lead poisoning include headaches, joint pain, fatigue, muscle ache, clumsiness, nervousness, a poor appetite, metallic taste in mouth, irritability, sleeplessness, abdominal pain, and constipation. Adults may also have impotency, decreased fertility or miscarriages. Children may also have behavioral problems and learning disabilities. Symptoms of severe poisoning may include nausea/vomiting, loss of balance, stupor, seizures, coma, and blue tints to gums and skin under fingernails.
Exposure Limit Information
Lead is a recognized health hazard. Consequently, exposure limits have been developed to protect people from excessive exposure. Lead exposure limits that are either regulated or recommended by government agencies include:
- OSHA (Occupational Safety and Health Administration) – sets regulatory limits for workplace daily airborne exposure to lead and the levels permissible in the bloodstream of workers with occupational contact with lead. The current lead exposure limits for workplace air are 50 mg/cm3, with an action level of 30 mg/m3. The current blood lead limits are 40ug/dl. The regulations are enforced by the Iowa Occupational Safety and Health (IOSH) Enforcement in the Labor Services Division of Iowa Workforce Development.
- EPA (Environmental Protection Agency) – sets regulatory limits for the amount of lead contained in paint, dust, and soil in and on the grounds of pre-1978 housing and child occupied facilities. The current exposure limits are: 40 ug/ft2 for floor dust; 250 ug/ft2 for interior windowsill dust; 400 ug/ft2 for bare soil in play areas; and 1,200 ug/ft2 for bare soil in non-play areas. These regulations are enforced by the Iowa Department of Public Health.
- EPA – has a regulatory limit for lead levels in ambient air to remain at or below 1.5 ug/m3 as averaged over a 3 month sample period. This regulation is enforced by the Iowa Department of Natural Resources.
- EPA – recommends a maximum concentration of lead in drinking water of 15 ug/L of water. This regulation is enforced by the Iowa Department of Natural Resources.
- CDC (The Centers for Disease Control and Prevention) - recommend all children be screened for blood lead levels once per year, especially between the ages of 6 months and 6 years. Children with blood levels at or in excess of 10 ug/l should be included in a childhood lead prevention program. These recommendations are supported through the Iowa Department of Public Health.
Guidelines for Minimizing Lead Exposure
- Employers need to be aware of materials in their workspaces that contain, or are suspected of containing, lead
- Employers must assume that all materials suspected of containing lead do contain lead unless proper testing proves otherwise. Determining the concentration of lead in materials is done by analysis of samples taken by trained professionals using appropriate and approved sampling methods. Lead swab testing (sodium rhodonzonate) is not an approved method to test for either the presence or concentration of lead in materials.
- Employees who perform activities that could potentially disturb materials containing or suspected of containing lead, must receive specialized training. Employers are responsible for training their employees on the health effects of lead exposure, and the types and locations of lead-containing materials in their workplace.
- Employees must be trained to not disturb materials containing or suspected of containing lead, or be made aware of tasks that do and do not create significant lead exposure. Employers must also provide their employees with equipment necessary to perform the tasks safely and comply with federal and state regulations pertaining to lead.
- Employers not familiar with regulatory requirements should obtain guidance when planning renovation, remodeling, or demolition work that could involve disturbing materials suspected of containing lead. Requirements include specific procedures, training, and licenses.
Tasks that Do Not Produce Excessive Exposures
These tasks are normally considered as not producing excessive exposure to lead. This is not a complete list of tasks that do not produce excessive exposure to lead. It does not exclude the possibility that a task on the list could be performed in a way that could produce excessive exposure to lead.
Tasks generally not requiring precautions and/or protective measures for lead exposure include:
- Removal of nails, screws, picture hangers, or other fasteners, etc., from a painted wall surface.
- Removal of cover plates, switch covers, etc., from a painted surface.
- Removal of hinge pins or painted door hinges.
- Removal of lock hardware, closers, or other hardware accessories from a painted door.
- Wet sanding drywall compound or spackle using a sponge.
- Separating and removing anything attached to a painted baseboard.
- Planing painted wood with manual tools.
- Drilling or preparing a painted door from installation of new door hardware (lock set, closers, kicker plate etc.).
- Re-nailing or refastening loose building trims, moldings or panels.
- Re-glazing of window glass.
- Removal of painted phone line or electrical wire.
- Freeing an inoperable window.
- Housekeeping, including emptying trash, vacuuming carpets, dust mopping hallways, cleaning water fountains, buffing floors, and disinfecting bathrooms.
- Maintenance, including replacing air filters, replacing toilet flush valve, replacing light bulbs, checking and repairing shower valves, unclogging a shower drain using a “snake,” mechanical repair of an air-conditioning unit, and repairing a shower leak.
- Carpentry activities, including removing wooden windows to measure to make screens, sweeping out the carpentry shop, planing the edge of a door and re-installing the hinges, re-hanging the door, removing outside entrance door, removing the kick plate, and removing the screws.
- Carpentry activities, including removing door hinges and lockset and replacing.
- Carpentry activities, including sanding floor with “stand-behind” power disc sander, scraping floor near corner, cleanup of debris, and placing debris in container.
- Carpentry activities, including wet hand scraping and wet sanding a column.
- Carpentry activities, including removing painted baseboards, cutting and pulling up wall-to-wall carpeting, scraping walls near baseboard, scraping carpet adhesive residue from floor, and sweeping floor.
- Carpentry activities, including removing window casing and painted molding, removing the window sash, heating the glazing, scraping and removing the softened glazing, re-installing the sash, re-hanging the window, and installing the wooden molding.
- Removing old plaster and re-plastering, manually sanding new plaster.
- Maintenance activities, including wet scraping of window and door.
- Plumbing activities, including manually removing old lead and oakum from around shower drains, heating lead in an open ladle using a propane torch, pouring the molten lead from the ladle into the cavity surrounding the drain, rapidly cooling the unused hot lead using cooling water from a sink faucet.
- Chipping and sanding plaster.
- Painter activities, including spreading plastic material around the hot-water radiator and wet scraping old paint from hot-water radiator, folding up the plastic on the floor, broom sweeping the floor.
Tasks that May Produce Excessive Exposure
These tasks are normally considered as capable of producing excessive exposure to lead. This is not a complete list of all tasks capable of producing excessive exposure to lead. It is possible that a task on the list could be performed in a way that would not produce excessive exposure to lead.
Tasks that may require precautions and/or protective measures for lead exposure include:
- Cleaning damaged or deteriorated lead based paint surfaces.
- Removing lead based paint chips and debris.
- Removing small areas of lead based paint.
- Wet sanding of lead based paint.
- Penetrating lead based paint.
- Removing components from lead based paint surfaces.
- Attaching to a lead based paint surface.
- Applying coatings to lead based paint surfaces.
- Installing materials over lead based paint surfaces.
- Enclosing a lead based paint surface.
- Exposing Lead Based Paint contaminated cavities.
- Lead based paint door and window maintenance.
- Changing filters and waste bags in lead based paint contaminated HEPA vacuums.
- Cleaning lead dust contaminated carpet.
- Landscaping in soil containing elevated levels of lead based paint.
Tasks that Do Produce Excessive Exposure
These tasks normally produce excessive exposure to lead. This is not a complete list of all tasks producing excessive exposure to lead.
Tasks that require precautions and/or protective measures for lead exposure include:
- Welding, cutting, or torch burning and related activities on lead containing materials.
- Abrasive blasting and related activities on lead containing materials.
- Dry sanding, scraping, or demolition and related activities on lead containing materials.
- Heat gun or burning removal of lead based paint from surfaces.
- Spray painting with lead based paint.
In accordance with OSHA standards, any employee who performs construction work and is occupationally exposed on any day to an average airborne lead level of 30 ug/m3 or higher, shall have initial medical surveillance. Employees occupationally exposed to an average daily airborne lead level at or above 30 ug/m3 for more than 30 days in any consecutive 12 months, will be offered scheduled lead medical surveillance per OSHA regulations. Also, initial medical surveillance will be done on any employee if the attending physician has reason to suspect may have been exposed to high levels of lead. The University Employee Health Clinic provides medical surveillance.
A medical examination shall be provided annually for any employee who has had a blood-lead level of 40 ug/dl or greater, or has been medically removed in the past 12 months. A medical exam shall also be provided to any employee in a lead medical surveillance program, for any of the following circumstances:
Employee experiences symptoms consistent with lead intoxication.
Employee needs consultation concerning the potential effects of past lead exposure or on the ability to procreate or carry a healthy child.
Employee has difficulty breathing during fit-testing or use of a respirator.
Prophylactic chelation may only be performed by a licensed physician and conducted in a clinical setting with thorough and appropriate medical monitoring. The employee must be notified in writing by the UIHC Workers Health Clinic prior to performing chelation. (External physicians planning on performing chelation must first notify the employee and the Workers Health Clinic).
Medical Removal Protection
Any employee who has a blood lead level of 50 ug/dl or more shall be excluded from work that has potential for lead exposure until the employee has had two (2) consecutive blood samples at or below 40 ug/dl.
Any employee may also be excluded from lead-related work when results of a medical consultation determine that the employee’s health may be at risk of impairment from exposure to lead. The medically removed employee may return to former duties upon receipt of a written opinion from the consulting physician that the conditions placing the employee at increased risk are no longer present or of material concern.
Waste Disposal Guidelines
EPA standards determine whether the waste must be managed and disposed of as hazardous or nonhazardous waste. Waste containing lead must be managed and disposed of as hazardous waste unless the laboratory EPA TCLP test characterized the waste as containing less than 5 mg/l of lead.