The purpose of this article is to give homeowners sound and usable information regarding the realistic hazards of lead and lead paint exposure. Lead paint is defined as any surface coating that contains lead in amounts equal to or greater than 1.0 milligrams per square centimeter or 0.5% by weight (which is the same as 5000 parts per million). Lead paint was in common use up until 1978 at which point it was banned by the Consumer Product Safety Commission. It is estimated that 64 million housing units in this country contain some lead based paint. If you own a home this is older than 1978 there is a very good chance that you have lead paint or lead based plumbing components in your home. And even if you have completely renovated your home, lead dust may still exist in the home or the soil adjacent to your home.
From 1986 through 1991, the EPA promulgated regulations controlling lead in drinking water to prevent the use of lead containing plumbing materials. This culminated in the “National Primary Drinking Water Regulation for Lead” under the Safe Drinking Water Act. Ultimately, all plumbing fixtures and parts were to be free of lead (not more than 0.2% lead in pipes and fittings) by late in 1998. And as you may remember, leaded gasoline was phased down through the 1980’s and ultimately banned by the beginning of 1996.
So it sounds like the government is very concerned about exposure to lead. And as you read on, you will understand why. Exposure to lead may be one of the more common and most devastating exposures in recent history. Today, as the study of lead exposure progresses, the call is being made for reducing exposures further. So let’s learn the facts and a few concerning anecdotes regarding your potential exposure to lead.
How Much Is Too Much?
Here is a link to a an article by Mother Jones from February 2013 (discussing a supposed link between blood lead levels and crime.) Now in this article they are discussing lead exposure by the way of vehicle exhaust and it is fair to say that there may be some room alternative theories. But what the author portrays concisely is the devastating effect that lead has on the brain, especially those of younger people. The effects are identical if the exposure is from lead paint or lead in water. But there is a clear correlation between the phase out and ban of leaded gasoline and measured blood lead levels (BLL’s) in children. Regardless the source of lead, The Agency for Toxic Substances and Disease Registry are among many others in citing the long term effects on intelligence, motor control, hearing, and emotional development.
Blood lead levels (BLL’S) are measured in micrograms per deciliter. A deciliter of blood is one ten of a liter and there are about 50 deciliters of blood in a typical adult human and 1 liter in a small child. A microgram (ug) is one millionth of gram. To get a grasp on that; a grain of rice weighs about 30,000 micrograms. So if you’re ready to indulge in some rather unpleasant numbers, here it goes;
The CDC recommends that 5ug/dl be used as an action level for children up to five year old, and that at 15 ug/dl individual case management is required. At 20ug/dl, you should be seeing a physician. For adults, OSHA has established an allowable blood lead level of 40 ug/dl and at 50 ug/dl the worker must be removed from exposure. Here is a link to the CDC Lead information page:
And for you painters, start at the following link but don’t go away because later in this article you are going to find out that you are part of the solution to lead poisoning, whether you want to be or not.
Childhood Exposure: How Does It Happen?
The predominant sources of lead in the environment where a child lives or is educated are from lead in paint or paint dust, soil contaminated by vehicle exhaust or house paint, plumbing systems, municipal water supplies, cooking and eating utensils (especially ceramics), some traditional medicines, food grown in contaminated soil, shooting activities, the clothing of painters and renovation contractors who are parents and foreign canned food. The main mode of lead intake for children is through ingestion. Children are more likely to crawl or be in contact with lead contaminated surfaces such as soil, household floors and window sills. Children are also more likely to engage in hand to mouth activities while crawling about or playing with toys. Lead can also be absorbed readily through the lungs. Studies indicate that from 20% to 50% of ingested lead is absorbed into the blood. So if you are ready for some math, let’s see exactly what it would take to produce a toxic lead level in a small child.
A 30 pound child has approximately 1 liter of blood, or 10 deciliters.
The lead action levels for a child is 5 ug/deciliter, acc. to the CDC.
The total blood lead weight to reach the action level then is 5ug/dl X 10dl = 50 micrograms.
Since half of ingested lead is absorbed, the child must consume; 50ug X 2= 100ug of lead.
We know that white house paint contained up to 50% lead before 1955. Federal law lowered the amount of lead allowable in paint to 1% in 1971. The CPSC has limited since 1977 the lead in most paints to 0.06% (600 ppm by dry weight).
So let’s assume that you have a newer than 1971 but older than 1978 home with 1% lead paint (which equals 1 ug of lead per 100 ug of paint). To achieve a total consumption of 100ug of lead in the blood the child must consume:
100ug lead x (100 ug paint/1 ug lead) = 10,000 ug of paint.
Remember that grain of rice? It weighed 30,000 micrograms (ug); three times the minimally toxic dose for a 30 pound child…..
So, if you have a grasp on that, the following will make a lot of sense (if it doesn’t just call me sometime and we can go over it). The EPA has established the maximum “Dust Lead Level” for several surfaces. They arrived at the following numbers partly by following similar calculations but mostly through extensive studies of exposure mechanisms in actual settings.
Lead Dust in Homes and Soils – What is Hazardous?
The EPA and the State of Colorado have developed a standard level of lead dust, beyond which is considered a hazard. That level is 40 ug/s.f. for floors, 250 ug/s.f. for window sills, 400 ug/s.f. for window troughs, 500 ug/s.f. for exterior window troughs, 500 ug/s.f. for exterior sills, 800 ug/s.f. for exterior paints, (s.f. = square foot). For soils: 400ug/gram in play areas and 1200 ug/g elsewhere. Based upon these numbers, how much lead dust is required to contaminate a 2500 square foot house.
2500 s.f. X 40 ug/s.f. = 100,000 micrograms of lead dust. Roughly the equivalent of 3 grains of rice, by weight. Since it is likely in a paint matrix, the actual amount of dust will be approximately five to one-hundred times greater.
As you can see, it does not take a lot of lead paint dust to contaminate a home. Immediately, you may think that you should remove all the lead paint on or in your home. Not necessarily; undisturbed lead paint in good condition is not a problem. The problem arises during activities that generate lead dust. And there a few more than you might think.
Renovation and Restoration Activities as a Source of Lead Contamination
The most significant source of lead dust in a home is often due to renovation activities. As expected these activities generate a considerable amount of dust. As of April 22, 2010 Ethe EPA has instituted new rules that affect people engaged and restoration, repair and painting. “EPA’s Lead Renovation, Repair and Painting Rule (RRP Rule) requires that firms performing renovation, repair, and painting projects that disturb lead-based paint in homes, child care facilities and pre-schools built before 1978 have their firm certified by EPA (or an EPA authorized state), use certified renovators who are trained by EPA-approved training providers and follow lead-safe work practices.” You can learn more here.
Essentially, the rule requires all contractors that engage in these activities to follow lead safe work practices if they work in pre-1978 housing or child occupied facilities. If your contractor is not RRP certified, find someone else.
The work practices for lead based paint activities differ significantly. The use of special control techniques and special equipment are the key differences. In many of the outlying areas of Colorado (think Ouray, Telluride, Montrose, Delta, etc.) contractors have been slow to step up. As with many environmental regulations, information is slow to trickle out of the centers of regulatory influence. And you may find that those charged with building safety and codes in your area are either not aware or unwilling to enforce codes that are not within their jurisdiction.
If you own a pre-1978 home or child occupied facility, the odds are good that these new regulations were virtually ignored during any previous renovation that has occurred. The passage of time does not mitigate a hazard that may have been created several years ago. And even if you hired an RRP certified contractor, can you be sure that they have carefully addressed lead paint dust in your home or business. Remember the grains of rice? Well there is a simple way to find out if your home is contaminated by lead dust. But before we discuss that, let’s look at other sources of lead dust exposure.
Other Sources of Lead Dust Exposure
Remember, that paint in good condition is not a hazard. However, there are things that can make lead paint become of hazard. Damage from friction, chewing, impact are significant sources of lead dust. Windows are of particular interest, partly because the durability of lead paint made it a preferred choice for places like window, jambs, troughs and sills. If your windows are not painted shut, you may actually still use them for fresh air. Each time you open and close a window, a small amount of paint dust is created. That dust is deposited upon the sill or trough, and some of that is disbursed as the breezes blow through. It has also been found that children seem to have and attraction to certain painted surfaces such as window sills. Teeth marks are a sure indication of potential lead paint exposure.
Lead paint was very common for wooden floors, especially exterior porches and stairs (both inside and outside). Over time the lead paint is worn away by foot traffic and tracked about the home. Foot traffic also brings in lead dust from other sources.
Exterior paint often had a very high lead content. As it flaked or chalked, the dust and particles would deposit around the home, contaminating the soil. Worse yet, it was not common practice to collect flaking lead paint while repainting a home. Lead may also be present in the soil from the historical accumulation of lead vehicle exhaust in high traffic areas. Contaminated soil from these areas can be tracked into a home. As previously mentioned, there are criteria for evaluating lead in soils including childrens’ play areas. And if you have a vegetable garden, lead can uptake into the plant tissues thereby contributing to another source of exposure.
Lead Hazards and the Screening, Assessment and Clearance Processes
Evaluating a building for potential exposures is fairly simple, if proper procedures are followed. In Colorado, specially trained persons called Risk Assessors are equipped to provide the necessary testing and inspection. Two standard practices are generally used: a “lead hazard screen” or a full “risk assessment”. But remember, these types of inspection are only relevant in pre-1978 housing and child occupied facilities.
The lead hazard screen is typically used in home or building that is in good condition or that has an unknown renovation history. The purpose is to determine hazards that you may not see or to determine that lead hazards are likely not present. If potential lead hazards are found, more detailed assessment and testing is warranted; a Risk Assessment.
The testing procedures are very similar for either a screen or risk assessment. In either case, if paint is found that is in poor condition (worn, cracking, peeling, etc.) the paint will be sampled for analysis of lead content. Dust will be collected from floors and window troughs following specific procedures for laboratory analysis. Soil is analyzed may also be analyzed as well. Though typically not part of a screening process, it is still advised if vegetable gardens or play areas are regularly used at the site. In some cases, water samples may be taken, especially if the piping in the home has not been recently replaced.
The results of a screening process will provide a high level of scientific confidence as a “negative screen”. Meaning that if the results are negative for lead, and conditions within the home do not change, there is likely no exposure problem. If lead is found, further testing may be warranted as well as the development of Hazard Control Plan.
Another form of risk assessment is a pre-renovation lead based paint inspection. This is required prior to renovation of any pre-1978 housing or child occupied building. The process involves a systematic way of collecting paint samples for laboratory analysis. The results of the testing will determine if special lead based paint controls and personnel are needed prior to renovation.
Once the renovation is complete, a simple process of collecting dust samples from floors and windows should be done. This will determine if any remaining dust exceeds the standards set forth in Colorado Regulation No. 19, The Control of Lead Hazards.