Lead-based paint is the main source of exposure to lead in older houses. Lead was used in villas in external and internal paintwork, flashings, valley gutters, heads to nails and waste pipes.
Care needs to be taken with all lead, although the greatest risk of lead poisoning is likely to come when paint residue containing lead is swallowed or fumes are inhaled.
The effect of lead is cumulative – it builds up in the body. Symptoms may include tiredness, poor sleeping patterns, moodiness, lack of appetite, and stomach pains. In extreme cases, it can lead to brain damage and can even be fatal.
If the renovation work on any house built prior to the mid 1960s involves removing many layers of paint from weatherboards or internal paintwork, there is a good chance that you will be dealing with lead paint in the older layers. Oil-based paints containing lead were commonly used until the mid-1960s when the health hazards of lead became more fully understood.
The use of white lead in paint was banned in 1979. Some special-purpose paints still contain red lead.
The removal of lead-based paint can result in harm to both the person removing the paint and people and pets in the vicinity. Young children are particularly at risk.
If a building is over 40 years old, assume that it may have been painted with lead-based paint at some stage.
Because inhalation of dust and fumes is the principal way lead enters the body, do not let paint debris become airborne during removal or clean-up. Take the following precautions:
- Use drop sheets. They should be fireproof if the paint is being burnt off.
- Wet sand to reduce dust.
- Fit a power sander with a vacuum dust bag.
- Wear a dust mask at all times.
- Collect dust and debris as work proceeds and bag or contain in a suitable closed container (such as strong plastic bags).
- Dispose in a place approved by the local authority.
If you wish to test whether a sample of paint includes lead, there are several options. Some paint stores sell a simple test kit that you can use with a chip of paint and some will even do a test for you, or can arrange one. There are also accredited laboratories that offer testing services for lead in paint. If you think lead from old paint or other materials may have found its way into the soil around a house, soil can be tested for lead too. Soilsafe Aotearoa has useful information and free testing.
There is an Australian/New Zealand standard that covers the management of lead paint on buildings – AS/NZS 4361.2:2017 Guide to hazardous paint management – Part 2: Lead paint in residential, public and commercial buildings. It covers methods for determining whether lead is present, and if so, how much, and how to choose an appropriate management strategy.