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Setting the scene

UK Approach to Risk Assessment of Genotoxic Carcinogens in the Occupational Setting Dr Susy Brescia Chemicals Regulation Directorate. Setting the scene.

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Setting the scene

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  1. UK Approach to Risk Assessment of Genotoxic Carcinogens in the Occupational SettingDr Susy BresciaChemicals Regulation Directorate

  2. Setting the scene • For some chemicals/uses (cosmetics, biocides for the amateur, food additives, etc), mutagenic property sufficient to ban/not authorise use by the general public no risk assessment required; • For industrial/professional uses of chemicals with a mutagenic property, societal position has been not to ban, but to seek to manage the risk risk needs to be considered.

  3. Legal framework for industrial/professional uses of chemicals • Chemical Agents Directive; • Carcinogens Directive; • REACH; • Classification, Labelling and Packaging Regulation;

  4. Genotoxic carcinogens: definition • Induce tumours, increase tumour incidence and/or malignancy or shorten time to tumour occurrence in animals or humans; • Evidence of mutagenic activity in vivo; • Assumption made – genotoxicity key event in mechanism of carcinogenesis

  5. Genotoxic carcinogens: identifiable threshold or not identifiable threshold? • Increasing evidence even directly acting genotoxicants have (rather than can be postulated to have) a biological threshold – difficult to identify experimentally; • Where mechanistic data available and practical dose threshold identified RA according to threshold approach; • Where threshold cannot be identified – we do not know whether a threshold exists (any exposure might carry some risk);

  6. UK approach to RA of non (identifiable)-threshold genotoxic carcinogens • A safe level of exposure cannot be identified; • No attempt to quantify levels of risk; • ALARP: reduce exposure ‘As Low As is Reasonably Practicable’;

  7. UK approach: why no quantification of risks?

  8. ALARP • Not a risk assessment methodology; • Risk management tool; • Emphasis on adequacy of controls to achieve sufficiently low level of exposure at which there could still be a level of cancer risk, but if so, the judgement is that it is low; • To ensure exposure is reduced at the lowest achievable and reasonably practicable level;

  9. Lowest Reasonably Practicable Level • In theory, balance between costs of controls and health benefits; In practice, as no estimation of risks, ALARP has been as low as possible without astronomic costs/closure of business; Or • According to REACH, in principle, level at which socio-economic benefits of the substance outweigh the risks; In practice, as no risk estimation in the UK, difficult to implement it in transparent manner; But • At this level still continuing duty on industry towards improved control

  10. Benefits and disadvantages of ALARP BENEFITS • Simple - based on hazard identification and exposure control; • No concerns about accuracy of risk estimates; • Regulators not forced to defend inaction at “acceptable/tolerable” levels of risks (10-6 is 200 in 20 million); DISADVANTAGES • Not completely transparent; • No absolute reference point – best practice tends to be current practice that is best;

  11. ALARP in practice in the workplace (1) • Elimination/total ban (M+U restriction/REACH restriction from 1 June 09) - technically and economically viable, less hazardous substitutes (underlying principle of CAD, Carc Dir and REACH) REACH Authorisation of nominated SVHCs (including genotoxic carcinogens): Industry to show • Invest in research of safer alternatives; • Develop substitution plan; • Continuing duty to improve controls;

  12. ALARP in practice in the workplace (2) • Very high level of containment - Closed automated systems; - Redesign of the process; - Engineering controls e.g. equipment under negative pressure; - Regularly cleaned and maintained equipment; - PPE (appropriate gloves, respirators and goggles) and LEV for system breaches (sampling, packing, maintenance/repair); But - Some processes less efficient/do not work when enclosed; - Costs for closed systems may be too high for small companies;

  13. ALARP in practice in the workplace (3) • Other measures to control risks - Dust and mist suppression methods (e.g. tablets or pellets rather than powder); - Control of staff to work area; - Change of PPE regularly; - Training of employees in the handling of dangerous chemicals; - Air and biological monitoring to show exposure levels are low and PPE is working; - Health surveillance;

  14. RA of genotoxic carcinogens: some personal thoughts • Unless dramatic scientific advance in developing methods to identify thresholds for genotoxicants, regulatory system has no magic solution to offer; • Both qualitative and quantitative approaches based on assumptions and not facts – hence inherently faulty; Question • From what we know today on the mechanisms of gentoxicity, is it time to push the boundaries?

  15. Is there a satisfactory alternative to ALARP?

  16. THANK YOU

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