Unveiling the Hidden Dangers: Understanding the Risk of Lead Exposure in Residential Homes

Hidden within the walls of countless domestic properties lies a hazardous legacy that continues to silently jeopardize the health of residents. The menace in question is none other than lead paint, an insidious relic from bygone eras. While regulations have restricted its use for decades, the long-lasting effects of lead-based paint still haunt older homes, casting a shadow of potential harm on those who reside within their walls. Understanding the risks associated with lead paint exposure is crucial, as it empowers homeowners and tenants to take proactive measures to protect themselves, particularly vulnerable children, from the perils that may lurk beneath layers of paint.

Why was lead added to the paint?

Lead was added to paint to improve certain properties of the finish. Lead was often added as a pigment that provides bright and vibrant colours. It was commonly used as a white pigment in paints, giving them excellent opacity and covering power. Lead-based pigments were also used for various other colours, including yellows, reds, and greens.
Lead-based paints were known for their durability and long-lasting qualities. They resisted cracking, chipping, and weathering, making them a popular choice for both interior and exterior applications.
Lead helped paint dry more quickly, allowing for faster production and application. It accelerated the drying process and facilitated the formation of a hard and smooth surface.

Lead-based paints were resistant to moisture, which made them suitable for use in high-humidity environments, such as bathrooms and kitchens.

Paints containing lead were less prone to mould growth and corrosion. They provided a protective barrier against these issues, increasing the longevity of the painted surfaces.

How did we recognise that lead poses a significant health risk?

In the 19th and early 20th centuries, as industrialization progressed, lead became more widely used in various applications, including paint, pipes, and gasoline. During this time, reports emerged linking lead exposure to health problems. Workers in lead-related industries, such as painters, potters, and lead smelters, showed signs of lead poisoning. These observations raised concerns about the health risks associated with lead exposure.

In the mid-20th century, extensive scientific research began to unravel the toxic effects of lead. Studies conducted on both animals and humans revealed that lead could accumulate in the body over time, causing damage to multiple organs, including the brain, kidneys, and nervous system. Researchers also found that children were particularly vulnerable to lead poisoning, and exposure during early development could lead to long-lasting cognitive and behavioural impairments.

As scientific evidence accumulated, governments and health organizations started taking action to protect public health. The use of lead-based paint was gradually restricted or banned in many countries, starting in the 20th century. Lead was also phased out of gasoline, as it was a significant source of environmental contamination and exposure. Today, there are strict regulations in place to limit lead exposure, especially for children.

These days and 32 years after being banned in England we are still dealing with historic legacies of lead use. The Victorian era and up until about 1970’s represented a peak in lead paint use in England.
 
What happens when lead enters the body?

When lead is ingested and absorbed into the body, it can damage the brain and other vital organs, such as the kidneys, nerves and blood. Lead may also cause behavioural problems, learning disabilities, seizures and in extreme cases, death. Lesser symptoms of lead poisoning include headaches, stomach-aches, nausea, tiredness and irritability.

How lead toxicity manifests depends on both the Blood Lead Concentration, and how rapidly Blood Lead Concentration rises. At concentration exceeding >30µg/dl symptoms such anaemia or abdominal pain may manifest. Lead exposures resulting in a lower Blood Lead Concentration may not cause such apparent symptoms, but still cause harm, particularly to the central nervous system. Decreased intellectual function and possibly other neuro-behavioural problems such as shortening of attention span. Lead is poisonous to the brain and nervous system, even in small amounts. There really is no safe level of lead in the blood.

The relationship between the Blood Lead Concentration and various symptoms is further explored in our article “Making Sense of Lead Blood Limits”.

How big is the lead paint exposure problem in the UK?

Based on the recent government statistics there were 121 cases of lead exposure in children identified in 2021 with the average detection (2015-2021) rate of 7 cases per million children aged 0 to 15 years.

It is estimated that in the UK population as many as 3.2 million children have Blood Lead Concentration above the intervention concentration. Recent estimations by the Institute of Health Metrics suggest that there were 213,702 children aged 0 to 19 years with a Blood Lead Concentration of ≥0.24µmol/L (≥5µg/dl), and 29,036 children with Blood Lead Concentration ≥0.48µmol/L (≥10µg/dl).

In the period of 2015 to 2021, one death of a child occurred partly or wholly attributed to lead exposure. A case report has since been published, showing the death occurred in a two-year-old boy with pica and iron deficiency, who ingested lead-containing paint, resulting in acute lead toxicity.

Increased risk of lead poisoning in children with developmental disorders.

Children with developmental disabilities have been reported to have blood lead concentrations that are higher than those of other children. Iron deficiency may increase susceptibility to lead toxicity and can also cause pica, a high-risk behaviour. These children are at higher risk of exposure due to increased mouthing (or "pica") activity, which results in increased ingestion of lead from paint flakes, lead in soil, and other sources.

Ingestion of lead-contaminated water, soil, or dust, herbal medicine preparations, contaminated foods and spices, consumer products that don't adhere to safety standards (like paint on toys, make-up, lead crystal glassware, and jewellery), and secondary exposure from parental hobbies and occupations are other significant potential exposure routes for kids.

How is lead released into the environment?

For a lead-based paint to represent a health risk it firstly needs to be accessible for abrasion. In the houses which have been renovated in the last 20 or so years it is quite unlikely that the upper most surface is the actual lead paint. You are protected from old lead paints by the layers of new paint, but sanding, drilling, or other forms of disturbance will still break that barrier and potentially expose you to lead containing dust.

Secondly, how well the paint adheres to the underlying surface is one of the main indicators of lead exposure risk. Flaking paint which has become brittle and is easily broken into ever smaller bits represent a very high risk. Then surface paints are sanded, drilled or otherwise renovated particles of lead dust are released into the atmosphere. The dust contaminated with lead, accumulates on various household surfaces such as doorknobs, tables, books, and children's toys. Such dust can then be picked up by hands and subsequently ingested. Children are much more susceptible to lead contamination due to their inclination for exploring and tasting of objects. In some cases lead dust can be directly inhaled into the body. However, this is most likely to happen during or shortly after uncontrolled lead paint removal or intensive renovation.

Is lead paint ever safe?

Lead paint that is covered with layers of new paint represent a little risk when is in good condition and is not subjected to regular abrasion. Surfaces such as windows frames and door frames represent the high-risk location due to periodic movement and abrasion. When considering testing for lead these surfaces should always be tested.

If you have plans for renovations which will involve surface preparation before re-painting, you should consider the risk of exposing and disturbing underlying older paints. The best way to address the risk of lead paint is to fully identify the extent of lead paint in your home. There are a number of lead paint test kits available, but they suffer several shortcomings. For example, they may not identify underlying old paint beneath fresh coating thus giving you a false sense of security. They are also not a suitable tool to carry out a comprehensive survey of a property where up to 100-200 sampling points may be investigated.

In the short terms even lead paint can be safe if they are in good conditions. However, they represent a legacy problem which may significantly increase the risk at some point in the future. So, in the long-term lead paint will always represent a health risk unless they are fully removed from the property.