Guidelines for the Management of Lead-Based Paint
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APPENDIX 1: LEAD IN PAINT
A1.1 Domestic paints
It should be noted that the concentration of lead in domestic paints has declined dramatically in the past decades. It may thus be assumed that pre-1970 interior or exterior domestic paintwork is almost certainly lead-based, while pre-1980 paintwork may be lead-based. Post-1980 paintwork may generally be assured to have a very low lead content unless old stock or industrial specification paint was used inappropriately.
Paint formulations contain a variety of materials, several of which (such as lead, chromate and solvents) may be harmful to health under certain conditions. However, research has indicated that lead is presently the predominant public and occupational hazard associated with paint removal work in New Zealand.
Prior to 1945, white lead was extensively used as a pigment in paint, but after this date it was progressively replaced by titanium dioxide. Recognition of the hazards to health associated with lead in paint has since led to strict controls on paint lead content, and other forms of lead have since been withdrawn from paint formulations.
The following are estimates of when various forms of lead were controlled:
- White lead (basic lead carbonate) and lead sulphate were used as white pigments in domestic paints until the mid-1960s.
- Lead chromate (yellow pigment) was an ingredient in domestic paint until the late 1970s.
- Red lead paint (steel primer) is known to have been used as a wood primer until the 1980s.
- Calcium plumbate has been widely used as a roof coating for iron roofs from 1958 until the present time. It is now no longer manufactured and few stocks presently remain.
It is important to realise that the potential still remains for old or industrial specification paints to be used inappropriately in domestic situations.
A1.2 Other paints
Paints are widely used in other situations for protective and decorative purposes, and their formulations are many and varied. Ships and steel infrastructure such as pylons, towers, bridges and pipelines, often have high specification paints to provide corrosion protection. Some formulations may have appreciable lead content, but may also contain other materials which under certain circumstances may also give rise to a health hazard or environmental contamination.
Given the large surface areas involved, and the absence of occupants or residents, abrasive blasting and mechanical paint removal methods are often appropriate for such situations. However, this introduces a significant potential for operator exposure to hazardous materials. Furthermore, where the resulting debris is inadequately contained, collected or removed, localised environmental contamination may result.
It is beyond the scope of this guideline to address such occupational exposure and environmental contamination issues, although the general principles described in the following pages may be applicable.
A1.3 Extent of the problem
Despite the very low lead content of today's household paints, there remains a significant accumulation of lead in painted surfaces in the built environment. Lead-based paintwork in occupied properties may present a hazard where:
- paintwork is being removed using an inappropriate method, generating lead-contaminated dust or fume
- paintwork was in the past removed using an inappropriate method, resulting in high lead content in household dust and adjacent soil
- paintwork is in an advanced state of deterioration (ie, chalking or flaking)
- flaking paintwork has contaminated adjacent soil or vegetation
- paintwork is in a situation or condition where it may be consumed (directly or indirectly) by children or animals
- paintwork is continually scratched, scraped, rubbed or otherwise worn, particularly on windows, doors and shelves.
