Medir la relación entre la toma de decisiones y la implementación del sistema

Note

Chapter 4, ‘Healthcare waste definitions and classifications’ explains the basis for classification of different types of healthcare waste using the six-digit numbers in line with the EWC.

10 Table 14 summarises the classification, packaging and disposal for some of the most common hazardous waste emanating from laboratories. The table shows the waste classification alongside the transport classification. For transport, infectious substances must be classified as Category A or Category B:

• Category A – an infectious substance which is transported in a form that, when exposure to it occurs, is capable of causing permanent disability, life-threatening or fatal disease in humans or animals;

• Category B – an infectious substance which does not meet the criteria for inclusion in Category A.

11 This classification means that the infectious component of laboratory waste is considered as either Category A or Category B, which determines the requirements for colour-coded segregation, packaging, transport, treatment and disposal.

Microbiological cultures

12 The definition of cultures in ADR, for transport, is the following:

“Cultures (laboratory stocks) are the result of a process by which pathogens are intentionally propagated. This definition does not include human or animal patient specimens as defined in this paragraph.”

13 Cultures will include HG2, HG3 or HG4 pathogens as well as Class 1, Class 2, Class 3 or Class 4 GMMs, whether in liquid (for example broth) or solid form (for example agar plate), or whether initiated from a laboratory stock or patient specimens.

14 Cultures are associated with high concentrations of microorganisms and a consequent increased risk of infection. This is particularly pertinent when the cultures are treated as waste, since – unlike culture samples, which will be used for further investigative purposes in an appropriate laboratory environment – waste cultures are intended for disposal and discard.

15 For organisms on the Category A indicative list found in Chapter 12, ‘Carriage information: Category A pathogen list’ (such as HG4 pathogens, many HG3 pathogens and some HG2 pathogens – for example Clostridium botulinum, poliovirus), the cultures must be classified as Category A waste. However, the indicative list provides examples and is not exhaustive; hence, there may be other microorganisms not on the indicative list that should be classified as Category A. The key consideration is whether they are:

“in a form that, when exposure to it occurs, is capable of causing permanent disability, life- threatening or fatal disease in humans or animals”.

16 If this were the case, the waste would not be considered suitable for classification into transport Category B, but would be transported and inactivated as per any Category A substance.

17 While the majority of HG2 organisms are not on this indicative list, it is important to consider the Category A criteria given above (that is, form of the cultures – for example their concentration, routes of transmission of the organism, host range, survivability in the environment, the quantity of cultures in any one consignment) before classifying HG2 organisms as Category B waste.

18 Whether classified as Category A or B, all cultures of pathogens (that is, HG2 to HG4 pathogens or Class 2 to Class 4 GMMs) should be inactivated on-site prior to final disposal because of the increased risk of exposure associated with the higher concentration of biological agents therein.

19 The Genetically Modified Organisms (Contained Use) Regulations specify where waste containing GMMs should be inactivated for Class 3 (within the laboratory suite) and Class 4 (within the laboratory) activities. Where CL1 and CL2 GM waste is being sent off-site for treatment, a derogation is required by the HSE, which is the competent authority.

20 While there is no specific requirement in COSHH to inactivate HG3 or HG4 cultures on-site, there is a requirement to achieve complete compliance with the general provisions. In particular, Regulations 7(3) and 7(4) place a duty on employers to apply control measures (including safe handling, storage and transport of biological agents, and such waste, at the workplace) consistent with the risk

assessment, which reduce to a minimum the number of employees (and others) who may be exposed and the level/duration of exposure. Based on this requirement, where the risk assessment identifies a significant risk of exposure (to the community) during transport and disposal of waste (that is, of exposure to some HG2, and most HG3 and HG4 pathogens), on-site inactivation before final disposal would be required in order to comply with COSHH.

Clinical specimens

21 Clinical specimens should have been sent to the laboratory as Category A or Category B and therefore should be disposed of as waste in the same manner unless they have been neutralised to make them non-dangerous.

22 Clinical specimens are defined for transport thus: “Patient specimens are human or animal materials, collected directly from humans or animals,

including but not limited to, excreta, secreta, blood and its components, tissue and tissue fluid, swabs, and bodily parts, being carried for purposes such as research, diagnosis, investigational activities, disease treatment and prevention.”

23 It is therefore strongly recommended that unless it is known, or reasonably believed, to contain infectious substances of Category A, all human or animal material should be regarded as UN 3373.

24 When clinical specimens are discarded, they will form part of the laboratory waste stream and need to be managed appropriately. The infectivity associated with this waste type is highly variable and needs to be considered as part of a risk assessment (as indicated in Figure 4). In the laboratory sector, this means that the bulk of specimens resulting from diagnostic investigations within clinical laboratories (for example

haematology, cytogenetics, serology) will have a low probability of containing pathogens.

25 However, clinical specimens used for

microbiological testing are more likely to contain pathogens, and segregation into the two categories will need to be considered as part of the risk assessment as indicated above.

26 To inform the risk assessment, positive specimens from CL3 and CL4 should be classified as Category A waste and those from CL2 be classified as

Category B waste.

Environmental samples

27 A similar risk assessment needs to be made for environmental samples (non¬human/animal- derived).

28 Where there is minimal or low probability of infectious substances being present (for example food screening samples, water, soil etc), waste specimens should be treated as non-infectious waste and in some cases Category B waste. However, where the environmental samples are from an outbreak scenario (for example Ebola virus), the samples should be treated as waste potentially containing Category A substances until the sample’s test result is negative.

Autoclaved laboratory waste

29 Waste from laboratories (particularly clinical microbiology) that has been autoclaved on-site is no longer considered to be infectious or hazardous. However, such waste has traditionally been subject

to further treatment, rather than being sent directly to landfill, because of the public sensitivity

associated with clinical laboratory waste. For example, autoclaved infectious waste will usually follow the waste stream for materials potentially containing Category B substances.

30 For the purposes of classification, waste inactivated on-site should be considered as offensive rather than infectious waste, therefore ensuring that the waste will be subject to deep landfill.