Lead poisoning usually occurs over a period of months or years. It is a cumulative toxin that effects multiple body systems including the brain, liver, kidneys and bones.

Long-term health effects from lead exposure can include:

• Coma, convulsions and death
• Reduced brain functioning
• Anaemia, hypertension, renal impairment, immunotoxicity and toxicity to reproductive organs
• Irreversible neurological and behavioural effects

Symptoms of lead poising may include the following symptoms (though it is not uncommon for people to show no symptoms):

• Stomach pains
• Difficulty sleeping
• Constipation
• Loss of appetite

If the paint is in good condition, over-painted with lead-free paint, not easily accessible by children and is not going to be disturbed by any planned refurbishments, it may be best to just leave it and check the condition on a regular basis.

If the lead-based paint is in good condition and not on a surface likely to be chewed by children or animals, it can be over-painted with lead-free paint.

If paint is in a poor, flaky condition, or on a surface that is easily accessible to children or pets, or if you are planning to renovate the surface, it should be removed.

See WorkSafe NZ's guidance on safely working with lead-based paint.

According to the World Health Organisation, no known level of lead exposure is considered safe.

For lead in paint, a concentration of 0.1% weight for weight is considered lead-containing paint. Working on this paint will require controls to be put in place.

For soil, New Zealand Soil Contaminant Standards should be followed. This depends on the type of land use and the amount of produce that is consumed. Residential land where food is grown and consumed has a lower limit than industrial or commercial land.

If lead levels exceed the Soil Contaminant Standards, further investigation or remedial action is required. Remedial action may include ground cover, paving or soil removal.

Lead may be absorbed into the human body in a range of pathways. These may include:

• Eating crops grown in contaminated soil
• Exposure to contaminated soil by eating or skin absorption
• Eating livestock that have been exposed to contamination
• Drinking water from contaminated land
• Eating fish that have been living in waterways where lead contamination has leached in
• Exposure to waterways that has been lead-contaminated
• Inhalation of dust from lead-contaminated land