BCD 2018

INTERIORS 5 155 C AT H E D R A L COMMU N C I AT I O N S C E L E B R AT I N G T W E N T Y F I V E Y E A R S O F T H E B U I L D I N G CO N S E R VAT I O N D I R E C TO R Y 1 9 9 3 – 2 0 1 8 years of age, at blood levels of just 5 µg/dL (0.24 µmol/l) and even lower (see Further Information: WHO). Old buildings may also show higher levels of other toxic and heavy metals and metalloids. Zinc chromate, cadmium sulphide yellow, chromium trioxide, copper arsenate, arsenic disulphide, antimony trioxide, cadmium sulfoselenide red and impure barytes were all possible ingredients until as recently as 2007, and the first four of these are on the REACH list of substances of very high concern. Mercury, which was added to paint for its biocidal and preservative properties, was gradually replaced by substances such as ammonia and organic based preservatives from the mid-1950s to the late ‘70s. Simultaneous exposure to multiple heavy metals may produce a toxic effect that is additive, antagonistic or synergistic, and the combination of mercury and lead could have grave implications due to their suspected synergistic toxicity. HISTORY OF CONTROL While the 1930s and ’40s saw the highest lead concentration in paints, levels in most paints fell dramatically in the following decades. In 1963 and again in 1974, voluntary agreements between the Paintmakers Association of Great Britain (now the British Coatings Federation) and the government resulted in the labelling of paint which contained more than 1.5 per cent (15 g/kg) in 1963 and one per cent (10 g/kg) in 1974 of lead in the dry film. The agreements were embodied within BS4310 but paint which did not comply with the British Standard could still be sold. The European Directive 77/728/EEC introduced in 1984 focussed on consistent and reliable labelling rather than on banning high-lead paint. Labels were required to carry a warning that the paint contained lead or any other known toxicant and should not be used on surfaces liable to be sucked or chewed by children. Wood and metal primers, imported paints and exterior paints were not subject to formal regulation, while household decorative gloss paints, undercoats and varnishes continued to have lead-based driers added in concentrations below one per cent in the dry paint film. However, the availability of cheap viable alternatives such as titanium dioxide certainly helped to reduce or exclude lead- based compounds in indoor decorative paint finish coats. The Environmental Protection (Controls on Injurious Substances) Regulations 1992 implemented Directive 89/677/EEC . The legislation was specific to lead carbonate and lead sulphate rather than the full spectrum of lead pigments and driers. Similar UK legislation for cadmium followed a year later. These were superseded by the Controls on Dangerous Substances and Preparations Regulations 2006 and ensuing amendments. EU REACH took effect in 2007. Annex XVII of the regulation took effect in 2009. This takes a more complex chemical- specific approach rather than implementing maximum lead limits in architectural paint, and included restrictions on all ingredients known to be toxic. However, the use of lead compounds by ‘professionals’ was still permitted, subject to labelling restrictions. The UK also has wide-ranging ‘health and safety legislation. In particular The Construction (Design and Management) Regulations 2015 (CDM) puts a duty on the principal designer or contractor to identify and eliminate, as far as possible, foreseeable health and safety risks to any person. This specifically mentions ‘lead paints and special coatings’ as potentially hazardous materials. Occupational exposure to lead is embodied within The Control of Lead at Work Regulations 2002 (CLAW) and its associated Approved Code of Practice (ACOP) while other toxic metals are covered by Control of Substances Hazardous to Health Regulations . COSHH defers to CLAW in relation to lead but is relevant to other toxic metals in paint. Potential significant exposure of other affected persons (the public, visitors and the end-user) must also be considered. The full requirements of CLAW are triggered if there is a potential for ‘significant exposure’ of any persons affected by the work. This includes medical surveillance and air testing. Paint disturbance and removal is frequently referred to in CLAW and its code of practice as work subject to its control because it is likely to cause significant exposure. While it also indicates that materials containing less than one per cent lead may not be significant, the main point is that the exclusion depends on the process employed and the control measures applied. A lead and toxic metals in paint survey which identifies the general levels and distribution of paint toxicants can inform risk assessment, containment and waste management measures. However, the key requirement of UK legislation is the risk assessment, not the survey. This is confirmed by current HSE website FAQs (see Further Information) which specifically state that a lead paint survey is not a legal requirement. MANAGING THE RISKS Refurbishment or redecoration may represent a substantial risk factor for exposure to and contamination by lead and other toxins. However, with careful planning, preparation and implementation of site-specific measures and controls, the potential hazards are not prohibitive and the risks can be managed effectively. A plan for the management of the risks is suggested in the flow chart. The lowest risk options are associated with minimally invasive procedures, but if stripping is required the safest available option should be selected and the control measures tailored to that option. All exposure pathways should be considered but the most hazardous processes are those that generate airborne dust or fumes. The resulting contaminants are difficult to contain and are easily absorbed, giving rise to both inhalation and ingestion risks. They also generate the highest potential for the contamination of clothing, surfaces and the environment. However, a ‘wet process’ that eliminates airborne particulates may still carry some risk of contamination and ‘significant exposure’ from ingestion, while chemical stripping methods that dissolve the coatings may present an additional skin absorption risk. There is evidence that unacceptable levels of lead dust can arise from removal of paint with lead contents of 0.25 per cent or lower. In 2008 the Health Protection Agency (now Public Health England) reported that cases of lead exposure in children associated with paint have occurred at levels of 0.1 per cent. The important thing to note is that lead in paint or varnish does not suddenly become non-hazardous at one per cent (10,000 mg/kg) or even at 0.1 per cent (1,000 mg/kg). The scale of risk also depends on the levels and types of other toxic and heavy metals present, the quantity and thickness of paint present, the method used to disturb or remove it, and the measures taken to protect all those affected by the work or the contamination arising from that work. This includes avoidance of contamination of the indoor and outdoor environment, soil and surface water systems. If the risk factors are known, standard risk assessment models (following COSHH principles for example) can be applied to reliably assess the risk and identify the site-specific measures required to minimise it. Where severity is high, exposure levels should be kept low. How low depends on the likelihood of harm and knowledge of the harmful effects of exposure. In conclusion, paint or varnish should never be regarded as a completely inert or harmless substance. The risks need to be better evaluated and understood before work starts in order to effectively manage them. However, attempts to spread alarm or promote a lead remediation industry are not helpful and should be treated with caution because proper risk assessment requires a more holistic approach. Further Information A longer and fully referenced version of this article, including hyperlinks to the key regulations and organisations named, appears online at http://bc-url.com/lead-paint. D Brackenridge et al, ‘Non-occupational and occupational lead exposures reported to the UK National Poisons Information Service 2008–2010’, Clinical Toxicology , vol 50, 2012 HSE, ‘Frequently Asked Questions on Lead’ (www.hse.gov.uk/lead/faqs.htm ) IPEN, ‘Lead’, http://ipen.org/toxic-priorities/lead D Koh et al, ‘Can salivary lead be used for biological monitoring of lead exposed individuals?’, Occupational and Environmental Medicine , vol 60, 2003 Royal Commission on Environmental Pollution, ‘Lead in the environment’, HMSO, 1983 UN Environment Programme, Global Report on the Status of Legal Limits on Lead in Paint , 2016 WHO Regional Centre for Environmental Health Action, Lead FAQs (http://bc-url. com/lead) HESAAN SHERIDAN is a historic buildings and materials scientist with over 30 years’ experience of materials testing. He is the managing director of Heritage Testing Ltd (see page 158).

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