Management of Public Health Incidents: Guidance on the Roles and Responsibilities of NHS led Incident Management Teams - October 2011

ANNEX E Environmental Incidents

1. Definition of an Environmental Incident:

An Incident where the release of a potentially hazardous or toxic agent (a source) may result in exposure via the environment (a pathway) of a human population (receptors) creating a risk of adverse health impacts.

2. Environmental Incidents are distinguished from other types of public health incident in that, rather than being detected via the identification of cases of illness (an outbreak) an environmental hazard may be detected before it has caused any human illness. This creates more of an opportunity to intervene early to control the hazard and to minimise the risk of harm to any at-risk human populations.

3. The release of an environmental hazard (microbiological agent, chemical, radiation or physical hazard) may be detected by routine or targeted environmental monitoring before there is evidence of adverse human health impacts (e.g. detecting excess Cryptosporidium or aluminium in drinking water). Rather than wait until cases of illness actually occur before intervening, the priority will then be to assess the risk to human health and determine what action, if any, is required to mitigate the risk.

4. In some predictable scenarios, plans already exist to ensure a rapid response (e.g. the Scottish Waterborne Hazard Plan, site specific and COMAH plans). In others a generic incident response will be required that, in the absence of any other agency doing so, may need to be initiated by an NHS Board. In such scenarios the primary objectives of NHS Health Protection staff will be to ensure appropriate inter-agency liaison, rapid health risk assessment, to advise on appropriate risk management (control and prevention) options and risk communication messages.

5. Compared to conventional communicable disease outbreaks, incidents associated with the release of non-infectious environmental hazards (chemicals, radiation or physical agents) may develop very rapidly, leaving a relatively short time to organise a full response. Rapid inter-agency liaison, risk assessment and decision making are likely to be required. Decisions on action to mitigate the health risks may have to be taken despite having only limited environmental monitoring data. Unless or until improved information becomes available that enables giving advice on a less strict standard of protection, it may be necessary to adopt relatively precautionary measures early on.

6. In some environmental incidents, where it is rapidly apparent that there is little risk to human health and it is likely to remain minimal, an NHS Board may not be the most appropriate agency to chair a multi-agency IMT (e.g. the Maritime and Coastguard Agency (MCA) plan for off-shore incidents, where MCA takes the lead from the start). However, in the absence of any other agency doing so, NHS Board CPHM should be prepared to do so. Chairmanship may always be transferred, if necessary, to another more appropriate agency during an incident and transfer may in any case be desirable in the recovery phase of an environmental incident. In most cases where a multi-agency response is required, SCG plans will facilitate co-ordination of multi-agency response.

7. Environmental Hazards include:

Biological Agents

• live microbiological agents: bacteria, viruses, protozoa
• biological by-products: allergens, mould spores, pollen

Chemicals

• naturally occurring: ozone; CO₂, SO₂, fluorides (volcanic action) etc.
• man-made: industrial and domestic chemicals, chemical warfare agents

Physical Hazards

• natural and man-made particulate pollution:
  • PM10: hydrocarbon combustion, accidental fires and wild-fires
  • silica: quarrying, open cast mining, volcanic dust
  • asbestos: demolition dust, fire generated fibre dispersal
• extreme weather events: heat-waves, floods, extreme cold etc.

Radiation

• ionising e.g. gamma radiation
• non-ionising e.g. ultraviolet
• exposures from natural sources e.g. radon or man-made sources e.g. nuclear waste
• deliberate release e.g. polonium

8. Characteristics of Environmental Incidents

Not all incidents share the same characteristics. Incidents may be:

• Acute Episodes - unexpected with sudden onset but with little risk of causing a long term hazards
• Acute Exacerbations of Chronic Hazards - where an acute release is added to an existing hazard burden
• Mixed Acute and Chronic Scenarios - in addition to the risks from an acute release phase, a chronic environmental hazard may be created

9. Acute Episodes

• typically a sudden unpredicted release with little or no warning from e.g.
  • a fixed facility with pre-exiting incident response plans (COMAH) or a REPPIR site (i.e. a site under the Radiation Emergency Preparedness & Provision of Information Regulations 2001 which hold radioactive materials. As such are required to conduct a hazard identification and risk evaluation (HIRE) to be reported to the HSE.
  • transport related (chemical tanker accidents)
  • major fires (tyre dumps, industrial premises)
  • commercial or domestic situations
• due to accidental or deliberate action
• hazard release of uncertain nature and scale
• incident of variable duration: very short to potentially prolonged
• limited time for Public Health response and risk management interventions

10. Acute Exacerbations of Chronic Hazards

Acute worsening of pre-existing poor environmental quality, e.g.

• sudden deterioration in air quality in a local (poor) Air Quality Management area
• winter temperature inversion leading to trapped air pollutants in urban settings
• 'hot spots' of contamination detected in a known area of contaminated land

11. Mixed Acute and Chronic Scenarios

Acute event leading to creation of a chronic hazard e.g.

• fall-out of chemical pollution or radiation contaminating crops, ground, surface waters
• mass animal carcass burials leading to chronic leachate pollution of ground and ground waters

Challenges in Managing Environmental Incidents

12. Not all incidents impact significantly on human health. The NHS Board will need to determine which incidents require a public health response and which are primarily about managing the risk to another agency's/company's reputation and/or media and political interest.

13. Incidents may present little direct or immediate risk to public health (e.g. low risk of inhalation of contaminants) but may nonetheless have impacts on the physical environment which create a risk of secondary human health impacts (e.g. contamination of grazing pastures or food crops).

14. Incidents are often complex and fast moving. There may be significant pressure to provide rapid public health advice and re-assurance to both emergency responders and the at-risk communities. However, this may be difficult due to:

• gaps in basic knowledge and scientific uncertainty
• limited availability of environmental real-time monitoring data
• limited environmental monitoring capability (e.g. Fire Service /Police DIM equipment, local authorities air sampling equipment)
• lack of reliable information as a basis for health risk assessment
• significant uncertainties in risk assessment creating pressure to adopt a precautionary approach and maximal risk avoidance
• limited options for public health action, e.g.
  • sheltering
  • evacuation
  • decontamination
  • prophylaxis or use of specific antidotes
• a need for dynamic risk assessment - frequent review and updating of the risk assessment

Environmental Monitoring and Dynamic Risk Assessment

15. Where practical, an IMT should ensure that an agreed environmental monitoring strategy is developed to improve the availability of data on which to base health risk assessment. An environmental monitoring strategy should ideally focus primarily on providing enhanced data for risk assessing the potential impacts on at-risk communities, in addition to addressing the broader environmental impact.

16. Initial risk assessments and advice on control measures may need to be reviewed and amended as a situation evolves (Dynamic Risk Assessment), particularly where updated environmental monitoring data provides better quality information. Limited technical capacity and resilience may require that the IMT actively assists in co-ordinating a multi-agency monitoring effort to maximise the deployment of limited resources. This is particularly likely to be the case in airborne hazard incidents (e.g. significant chemical releases or fires).

Multi-agency Working

17. The range of agencies involved in managing an environmental incident is likely to be broader than for a conventional outbreak and would be co-ordinated under the auspices of the SCGs in accordance with 'Preparing Scotland'. These agencies may include:

• Emergency services: police, fire, ambulance
• Environmental regulators: Local Authority, SEPA, SNH
• National agencies: FSA, GDS, HSE, MCA
• Site operators and specific site plans (e.g. COMAH, Nuclear Site Plans, REPPIR site)
• Scottish Government, Civil Contingencies Unit
• Strategic Co-ordinating Groups (SCGs) and STACs
• AHVLA/SGRPID (Scottish Government, Rural Payments and Inspections Directorate) - for zoonotic disease

18. Sources of advice and expertise required to support an environmental incident IMT may also have to be wide and involve additional parties:

• Scientific Advisers to Fire and Rescue Services (FRS)
• HPA Centre for Radiation, Chemicals and Environmental Hazards
• Police CBRN Centre, Ryton
• DSTL, AWE and other MoD resources
• Industry and commercial sources

Potential Public Health Interventions

19. The 'source/pathway/receptor' model is useful in analysing an environmental hazard release scenario. A hazard may exist but unless there is a plausible 'source-pathway-receptor' linkage between the hazard and a population, then there is unlikely to be a significant risk to human health. Where a plausible linkage can be identified, then there may be a range of potential interventions to either eliminate the hazard or at least to mitigate the level of human health risk as indicated in the Environmental Incident Management Matrix (Figure A).

Figure A. Environmental Incident Matrix