Health & Safety at Little France: Disinfection & Decontamination

1. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Welcome to an on-line health and safety training package intended for staff and students working within UofE buildings on the Little France campus Information contained within these pages is intended for use by University of Edinburgh staff and students only.

2. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION This on-line training package is intended for laboratory-based workers, but is not a substitute for more detailed training which may be organised by laboratory managers. Last updated: January, 2018

3. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Please take time to view the following material, and direct any urgent questions to your H&S Advisor, Laboratory Manager, or the Little France Buildings H&S Manager (the contact details for whom are shown on the penultimate page of this presentation). Thank you

4. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION It’s important at the outset to understand that disinfectants are not the same as antiseptics; and that, in any event disinfectants rarely achieve a 100% kill rate in practice. What may be judged to be an acceptable degree of disinfection is, for example, a stated number of log kills (e.g. five or six log kills).

5. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Antiseptics are intended for the control of micro-organisms commonly found on skin or mucous membranes without damaging these tissues. They usually do not have the same killing power as chemicals used for disinfection of surfaces or equipment. For that reason, antiseptics should not be used in an attempt to disinfect surfaces and materials.

6. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Good laboratory hygiene most certainly includes efficient hand-washing. Use should be made of the soaps provided at hand-wash basins in all laboratories. Alternatives will be made available for those who have dermatological sensitivity to some components of the products that are routinely provided.

7. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Fumigation may be required before maintenance of biological safety cabinets etc, or following spillage of a higher risk micro-organism within a containment laboratory. This, though, is a highly specialised activity, with some potentially very hazardous aspects, which should be managed only by competent people, and the detail is beyond the scope of this simple presentation.

8. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Basically, though, fumigation commonly involves use of substances such as formaldehyde, hydrogen peroxide or chlorine dioxide, and the process is likely to entail periods of conditioning/dehumidification, gassing, a minimum dwell time, and subsequent ventilation.

9. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Fumigation of microbiological safety cabinets is required: • Before maintenance work, where access is required to (e.g.) filters that might be contaminated; • Before carrying out filter penetration tests; • Where there has been a significant change to the nature of work being done within the cabinet; and • After a spillage of pathogens, etc.

10. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Fumigation of whole rooms may be required: • Where there has been a significant change to the nature of work being done within the laboratory; and • After a spillage of pathogens etc. The integrity of the room must first be confirmed by smoke-testing to ensure that fumigant does not leak into occupied surrounding areas.

11. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Choice of a suitable disinfectant is influenced by several factors: • The micro-organisms to be disinfected • The nature of surfaces to be disinfected • The hazards to health that may be represented by the disinfectant • Stability of the disinfectant • Contact times • Validation requirements

12. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Micro-organisms: • Disinfectants may vary considerably in terms of their effectiveness against vegetative and sporulating bacteria, fungi, enveloped and non-enveloped viruses, mycobacteria, and prion agents. • Care should be taken to ensure that a chosen disinfectant will be effective against all micro-organisms known to be present in material to be disinfected, and also take account of the quantity of micro- organisms likely to be present

13. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Nature of Surfaces: • Disinfectants vary also in terms of their capacity to do damage to surfaces (e.g. hypochlorites can chemically damage stainless steel, resulting in corrosion or pitting of surfaces). • Disinfectant activity may be degraded by temperature, pH, water ‘hardness’, the presence of organic materials and some other chemicals, and how ‘dirty’ the surfaces are that are to be disinfected.

14. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION It may be necessary to add a mechanical process to enhance penetration of disinfectants through biofilms, etc.

15. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Hazards to Health: • The COSHH Regulations dictate a need to assess risks associated the chemicals capable of harming health. Chemicals that are capable of killing off micro-organisms almost inevitably have the potential to harm people too. • Useful information, and guidance relating to safe use, are readily available from manufacturers and suppliers in the form of safety data sheets, and must be incorporated into a formal risk assessment and safe system of work.

16. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Stability of Disinfectants: • Particularly once diluted from a stock preparation, the activity of disinfectants commonly degrades with time. • Product information sheets, supplied by manufacturers, will provide useful information, and laboratory standard operating procedures should take account of these properties so that no disinfectant is allowed to remain in a laboratory beyond the time at which it is no longer likely to be effective.

17. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Contact Time: Product information sheets, supplied by manufacturers, provide useful information regarding the minimum time that a disinfectant must be in contact with a micro-organisms to achieve sufficient kill, and laboratory standard operating procedures should take account of these properties so that staff are aware of the minimum necessary concentrations and contact time that are necessary for disinfection.

18. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Validation: • It may be necessary to demonstrate the effectiveness of disinfection (particularly for higher risk micro-organisms). • This may be done by attempting to culture micro-organisms from progressively more concentrated solutions of one disinfectant and recording the results in the form of a graph, or by subjecting one organism to several different disinfectants. • This may help set standards to be followed within laboratories.

19. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION • By the same token, the effectiveness of applying a disinfectant to a surface (for example) may be evaluated by attempting to culture contaminants from the targeted surface. • Since, though, incubation times may be extensive, and a negative culture cannot be taken as absolute evidence that disinfection has been complete, there may be limited value in undertaking such tests.

20. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Examples of disinfectants include: • Phenolics • Chlorine-containing compounds (or products which generate chlorine) • Alcohols • Aldehydes • Surface-active agents • Peroxygen compounds • “New disinfectants” • Ultra-violet radiation

21. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Source: KemI's Products Register. 

22. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Phenolics (e.g. Hycolin, Stericol, Clearsol, etc): • Works by causing cause cell lysis • Some may contain also detergents that work synergistically with the phenolic agent • Stability reduces with dilution • May damage plastics • Many phenolics have been outlawed in the EU

23. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Chlorine-containing or chlorine-generating compounds (e.g. Hypochlorite, Chloros, Presept, etc): • Works by denaturing proteins • Chlorine gas released when mixed with (e.g.) strong acids • Carcinogens may be formed by mixing with (e.g.) formaldehyde • Hypochlorites are the only disinfectants known to inactivate TSE prions

24. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Alcohols (e.g. Ethanol, Propanol, Industrial Methylated Spirits, etc): • Probably work by denaturing proteins • Use diluted (100% alcohol is a poor disinfectant) – typically 70% ethanol or 60% propanol • Should be used only on physically clean surfaces because of poor penetration qualities • Highly susceptible to interference • Flammability risk

25. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Aldehydes (e.g. Cidex, Gluteraldehyde, Formaldehyde, etc): • Irritant and toxic and potentially extremely hazardous • Specialised usage (e.g. fumigation) • Requires risk assessment and safe systems of work

26. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Surface-active agents (e.g. Cetrimide, Tego, etc): • Relatively non-toxic and non-irritant, but easily inactivated by organic matter and anionic detergents (e.g. soap)

27. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Peroxygen compounds (e.g. Virkon, etc): • Broad-spectrum disinfectant • Working solutions (1% w/v) have low toxicity and no irritancy • Virkon has a built-in colour indicator for effective disinfection capacity, and has detergent properties that combine disinfection with cleaning • May be corrosive to low quality steel surfaces

28. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION “New disinfectants” (e.g. New Hycolin, Trigene, Tristel, etc): • The effectiveness of these against some micro-organisms (e.g. mycobacteria is disappointing, or yet to be proved either way).

29. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Other disinfectants (e.g. Hibiscrub, Betadine, pHisomed, Cidal, etc): • Together with household disinfectants (e.g. bleach), these are unsuitable for use as laboratory disinfectants.

30. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Ultraviolet radiation: • UV-emitting bulbs degrade quite quickly and, though they may continue to emit a blue-coloured light, they will then have little or no germicidal effect. • UV light is directional, and cannot disinfect areas or materials that are “in shadow”. • Adverse health effects to operators may be associated with exposure to UV light.

31. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Ultraviolet radiation: Basically, therefore, after balancing off the significant risks against doubtful benefits, and recognising that there are perfectly good alternatives, it might be argued that UV radiation has no place in a safe and sensible disinfection strategy.

32. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Ultraviolet radiation: But, where it has been specially justified, suitable and sufficient risk assessments and safe systems of work must first be put in place.

33. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Other processes: • Wet heat (e.g. autoclaving) • Dry heat (e.g. dry air ovens) • Gamma irradiation • Filtration Each of these techniques has advantages and disbenefits, and these should be understood before opting to use any one of them.

34. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Further Information Further information relating specifically to disinfection is available at Appendix 15 of this site’s Safety Manual, which can be accessed at: https://www.ed.ac.uk/medicine-vet-medicine/staff-and-current-students/cmvm-health-and-safety/little-france/manual

35. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION

36. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Spill Management Information concerning aspects of autoclaving, and also regarding the correct management of chemical, biological and radiological spills, is available in separate on-line training packages, which you can access using the same pathway that you took to find this presentation.

37. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION A reminder … Disinfectants may be harmful to human health. Material safety data sheets should always be consulted, and a formal written COSHH risk assessment may be required for use of these within the laboratory.

38. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Problems and Questions Refer all other enquiries to your H&S Advisor, Laboratory Manager or the Little France Buildings H&S Manager as soon as possible.

39. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION Lindsay Murray Health & Safety Manager, The University of Edinburgh, College of Medicine & Veterinary Medicine (Little France/Bioquarter Campus) Room SU225, Chancellor’s Building Ext: 26390 lgm@staffmail.ed.ac.uk

40. HEALTH & SAFETY @ LITTLE FRANCE DISINFECTION & DECONTAMINATION You have now completed this on-line training package summarising the correct use and potential limitations of disinfectamts. Please also attend any additional training that may be organised by your senior laboratory manager. Thank you