Lead paint hazards in restoring meeting houses

Tu Tangata, Issue 23, 1 April 1985, Page 23

Lead paint hazards in restoring meeting houses

t is very pleasing to see all the work that is now being done to restore meeting houses. Marae committees are raising funds and financial help is being given by various government departments. Much of the work is being done through the Labour Department P.E.P. and Workskill schemes although many of the restorers are volunteers. People are realising how much the meeting houses mean to their mana and history.

But restorers should beware that restoration work can present a danger to health. Obvious examples are the chemicals used to kill moss, rot and borer. Some of these chemicals are very poisonous and should be used by only a few people who are aware of the dangers. If proper care is taken in using these chemicals, such as reading the instructions and storing them out of reach of children, there should be few problems. However, recent research has revealed a problem for which there is no answer as yet. This problem is the health hazards that can occur when paint containing lead pigments is removed. Research done by the Building Research Association of New Zealand suggests that in New Zealand about 250,000 dwelling houses probably have lead pigments in the paint used on outside walls, such as on timber weatherboards. Undercoats and gloss topcoats used before 1945 probably contain white lead pigments. After 1945 the use of white lead declined as other white pigments became available, but red lead was still used in wood primers for many years until its use was also stopped. House paints used today do not contain lead pigments. It has been estimated that some of the older dwelling houses (e.g. built before 1930) that have been well looked after and regularly repainted could have many kilograms of lead pigments in the old paint still on the timber. With the age of most of our meeting houses and the fact that redecoration in the past has been additional coats of paint rather than paint removal, it is reasonable to assume that all except the most modern meeting houses have paints containing lead. The white paint in the kowhaiwhai patterns on the heke probably used a lead pigment, yellow and orange paints on painted poupou panels also probably used other lead pigments and the primer beneath these paints could also contain lead pigments.

Lead can make people very ill and can cause a wide range of symptoms. The body can get rid of lead only very slowly so its effect can gradually build up over a period of time. A most serious side to lead poisoning is that it can affect the mental development of young children. Even small amounts of lead dust or paint chips breathed in or swallowed can have an effect. This point is worth remembering since the restoration of meeting houses is a family affair where parents and their children are all involved in the work. It should also be realised that lead from old paint which goes into the soil does not break down but adds to environmental pollution often very close to areas where people live, and can cause problems at a later time. The main danger with lead pigments in paint is when the paint is being removed and the dust and paint flakes are being blown around. In our museums the conservation work on carvings from meeting houses does not generally involve the removal of the paint. The various paint coatings are considered to be part of the history of the carving. There are notable exceptions like the Pukeroa Waharoa which was painted with red oxide paint by the Auckland Museum; this has now been removed to reveal the magnificent original colours and design. The restoration of meeting houses is somewhat different from normal museum conservation treatments. The tangata whenua have worked hard, they wish to be able to feel proud of the labour, so the house must look as bright as a new pin when the work is complete. Sometimes recent coats of paint have spoilt the original detail of design of the kowhaiwhai pattern or thick coatings have covered up the fine detail of the carving. The paint on the carvings outside in the weather is not sound enough to be painted over, therefore there are reasons for removing the paint on a meeting house. Before decisions are made to repaint a meeting house we recommend that all

the paint work is washed with a dilute solution of a special neutral detergent and then rinsed with clean water. Once the dirt and grime are removed it is surprising how different the paint work looks. If it is then decided to repaint but not to remove the old paint the surface can be sealed with a special clear sealer and then overpainted with modern water-based acrylic paints. The history of the old coats of paint have not been lost as the water-based acrylic paint can be removed with solvents and the clear sealer will protect the original paint from damage by these solvents. If it is decided to remove the original paint for the reasons previously stated, then the paint should be tested to see whether or not it contains any lead pigments. The following simple test for lead is easy to do and can be done on-the-spot:

Use a razor blade or sharp knife to cut or scrape a small area of paint so that all the layers of paint down to the wood can be seen. Make the test solution by dissolving a few crystals of sodium sulphide in water. A 5% solution by weight is sufficient. (A small amount of sodium sulphide should be obtainable from a local pharmacist. It has the smell of rotten eggs. If it loses this smell after some weeks it has gone off and a fresh solution should be made up. It is a good idea to store the test solution in a small dropper bottle. Place a label on the bottle showing what it is and store it in a safe place. An even simpler approach would be to show a pharmacist or chemist these instructions and to ask that a 5 % solution of sodium sulphide be made up ready for use.) Place a drop of the sodium sulphide solution on the exposed paint layers. Any layers of paint containing lead

will immediately turn black if lead pigments are present. Occasionally, other substances may give a dark colour when tested with this solution and it may be considered necessary to have other tests done on the paint to confirm the results. Department of Health Inspectors can do this, or paint flakes can be sent to the National Museum to be checked. At the present time we cannot recommend any completely satisfactory methods for removing old lead paint. Solvent or chemical paint strippers are somewhat messy and themselves contain dangerous or unpleasant chemicals. Kerosene or gas blow lamps can be used to soften paint to make it easier to scrape off, but the open flame is hot enough to burn the paint and generate lead fumes. These blow lamps will also burn the wood and introduce a serious fire hazard for buildings. If used carefully, hot air guns are better as they are not as hot as an open flame and there is less chance of burning the paint or wood. However, with both blow lamps and hot air guns it is still necessary to remove (scrape) the softened paint from the wood and therefore the problem still remains of safely disposing of the scrapings and dust. Other methods of paint removal such as sandpaper, wire brushes, sand-blast-ing and water blasting and the various attachments for power tools cause a

great deal of dust which is difficult to collect. Even power sanders with dustbag attachments do not control the dust very well. Another disadvantage of these methods is that they can severely damage the fine detail of the carving. We now have to ask what method is left for removing lead paint and which is not hazardous to workers or others in the work area? Lead paint may have to be removed from different types of surface, ranging from smooth flat timber to intricate carvings. At present, it seems that the safest approach is to scrape the paint away, with a vacuum cleaner handy all the time to collect scrapings and dust as it comes off. This allows a choice for using different scraping tools (and a hot-air gun if this helps) depending on the type of surface the paint is on. Scraping has the advantage over sanding that less dust is produced. Various types of scrapers are available from hardware shops, or homemade scrapers can be used. For example, simple and effective scrapers can be made from No 8 fencing wire with the aid of a file, hammer and hard surface for an anvil. The paint chips produced by scraping are easily picked up by a vacuum cleaner and this makes sure that all the lead dust ends up inside the vacuum cleaner bag to be disposed of later. The vacuum collection of the flakes and dust as you go also makes it easier to see how the work is progressing. Dust sheets must be placed and securely held down beneath the areas where the paint is being removed to catch any paint flakes not collected during the scraping-vacuuming operation. This sheet should be vacuum-cleaned at least twice a day to stop the lead paint flakes and dust being spread around. Tough plastic sheets are useful for this purpose because all of the material collected can be easily removed and the sheet washed off; whereas lead dust can be trapped in the fabric of a cloth material. Having collected the flakes and dust of lead paint with the vacuum cleaner, make sure that the rubbish is then properly disposed of. A good idea is to put all this waste into a strong (plastic) rubbish bag set aside for this purpose only. Be careful not to let dust fly up when emptying the vacuum cleaner into this rubbish bag. Some vacuum cleaners can be fitted with disposable bags which simply require that these disposable bags are tied up and placed whole into the rubbish bag. Tie the top of the rubbish bag securely and take it to a public tip or bury it well away from areas where people live. If working with lead-paints pay special attention to personal cleanliness: wash hands before eating or smoking; do not eat or smoke close to work areas; wash the skin and hair thoroughly each day; change from work clothes before leaving to do anything else; and wash work clothes regularly.

In situations where dust is released into the air, an efficient face mask should be worn. When many of our meeting houses were carved rules were imposed by the tohunga of carvings. Carvers were not allowed to blow loose chips from the carving; they were not permitted to smoke or eat when carving; when they left the carving area they had to wash their hands and when the carving was finished for the day all the chippings were gathered up. This procedure is an excellent guideline to follow when removing paint from carvings. It is as if the ancestors anticipated today’s problems. Until further research provides us with better restoration techniques we cannot provide a completely safe method to deal with the special health hazards that occur when meeting houses are restored, but at least we can be aware of the hazards and use the safest methods available. In the meantime we suggst that the following procedure is adopted: 1. Treat all chemical materials used in restoration as dangerous. Make sure they are clearly labelled, keep them locked away when not in use, and in the care of a few trained people. 2. Think very carefully before deciding to remove any paint; it destroys the history and could cause additional health hazards. 3. Test the paint to see if lead pigments are present. 4. Don’t use any paint removal methods that cause dust or lead fumes. 5. If paint containing lead has to be removed, use hand scraping tools of some kind and have a vacuum cleaner handy all the time to collect scrapings and dust as soon as possible after scraping. 6. Clean up regularly at least twice a day; vacuum clean the area, carefully store the paint dust and scrapings in a special rubbish bag and bury it at a rubbish tip. 7. Don’t blow on the surface, eat or smoke when removing paint that contains lead. 8. Make sure that there is good ventilation in the work area. 9. Wash your hands before eating or smoking. 10. Regularly wash working clothes to remove paint dust. For further details of lead tests or special conservation chemicals please contact the National Museum, Private Bag, Wellington. M.L. Jansen Materials Division Building Research Association of New Zealand J.I. Fry Conservation Officer National Museum