Unconventional oil and gas policy: SEA

13 Population and human health

What are the environmental effects of the reasonable alternative on population and human health?

13.1 Unconventional shale gas/oil development and CBM development could result in the following effects on population and human health:

• Health impacts associated with air pollution from direct and indirect sources associated with exploration, appraisal, production and decommissioning.
• Health impacts associated with water pollution from direct and indirect sources associated with exploration, appraisal, production and decommissioning.
• Noise, light, and odour issues from exploration, appraisal and production:
  • Noise impacts (from site activities and traffic associated with unconventional oil and gas developments).
  • Light pollution from site activities including floodlighting and flaring.
  • Odour nuisance.
• Health issues associated with induced seismic activity during exploration, appraisal and production.
• Impacts on local amenity and mental well-being, and access to opportunities for recreation and physical activity.
• Physical health and safety risks:
  • Increased risk of road accidents.
  • Accidental releases of hazardous materials.
  • Explosive risk (including waterborne methane)
  • Occupational risks associated with respirable crystalline silica.

13.2 The health impacts of air pollution are described in detail in the section on Air which explains the different air pollutants released by unconventional oil and gas development and their health impacts. Pollutants include methane (CH₄), carbon dioxide (CO₂), volatile organic compounds (VOCs), non-methane volatile organic compounds (NMVOC), nitrogen oxides (NO_x), carbon monoxide (CO), sulphur dioxide (SO₂), particulate matter (PM), and black carbon.

13.3 Air pollution due to gaseous and particulate hazards linked to unconventional oil and gas activities is a potential source of both short- and long-term adverse effects on human health. Evidence is well established that the main toxic pollutants can cause a variety of health effects including irritation of the respiratory system and exacerbate existing health conditions, especially heart disease and respiratory illnesses, in vulnerable individuals.^[254]

13.4 The health impacts of water pollution are explained in detail in the section on Water which explains the different sources of water pollution. Health impacts include carcinogens used in fracturing fluid, and naturally occurring radioactive material within flowback water.

13.5 Unconventional oil and gas developments have the potential to increase noise impacts on nearby residents. Site activities associated with unconventional oil and gas development that could increase noise impacts include drilling, completion operations, flaring and traffic movements to and from unconventional oil and gas facilities^[255].

13.6 Light pollution may be caused by lighting for safe working or flaring, particularly during the drilling phase which occurs 24 hours a day until complete. Truck movements may comprise another source of light pollution^[256].

13.7 Odours associated with unconventional oil and gas could potentially result in odour nuisance, particularly in neighbouring areas^[257].

13.8 It is documented that unconventional oil and gas developments can lead to induced seismic activity. When unconventional oil and gas wells are fractured, the rock breaks and causes locally detectable seismic events. Induced seismicity is often the result of long-term unconventional oil and gas production^[258,259]. Seismicity is associated with hydraulic fracturing, which is generally not required with the extraction of CBM^[260], although it can take place.

13.9 The risk of fracking-induced felt seismicity causing damage to properties or people at the surface is considered to be very low: very few earthquakes have been triggered by fracking for shale gas (3-5 documented cases of felt seismicity over millions of frack jobs, Davies et al 2013), and the hazard they pose is very small since the few incidences of felt seismicity were at such small magnitudes that they caused little or no environmental effect or damage to the built environment.^[261] However Health Protection Scotland^[262] concluded that there was ‘inadequate’ evidence that seismicity linked to unconventional oil and gas activity was associated with any actual physical risk to health. Furthermore natural seismicity is low in the Central Belt of Scotland, where natural (background) earthquake activity almost all occurs north of the Central Belt, or south of the Southern Uplands^[263].

13.10 Impacts on local amenity and well-being relate to wider environmental quality, such as landscape, amenity and access to recreational resources, and the associated direct and indirect effects on health and well-being.

13.11 Physical health and safety risks are associated with unconventional oil and gas development, such as the physical risks associated with respirable crystalline silica^[264] and the immediate physical risks caused by potentially explosive mixtures of methane and air. Such risks particularly apply to unconventional oil and gas industry workers^[265].

13.12 There is the risk of accidental releases of hazardous materials (e.g. wastewater spills) during transportation, particularly if a collision involves a vehicle carrying dangerous substances. The release of hazardous materials could have the potential to adversely impact upon public health^[266].

13.13 Unconventional oil and gas development would lead to increased traffic movements and heavy vehicle movements. These additional vehicle movements could potentially result in an increased risk of road accidents^[267].

How do these effects relate to the current pressures and trends?

Deprivation and health

13.14 There are established links between deprivation and health and this is further contributed by links between environmental quality and deprivation. Air pollution is often worst in urban deprived areas, worsening existing inequalities in local environmental quality and human health.^[268] The areas of Scotland experiencing the highest levels of multiple deprivation are illustrated on Figure 4a and 4b, Appendix 1, and this shows a correlation between the prospective areas for unconventional oil and gas development and a number of areas within the 20% most deprived areas. Similarly, those parts of Scotland in the 20% most deprived areas for health deprivation include areas of Fife, Edinburgh, Falkirk, North Lanarkshire and Glasgow which lie within the prospective area for unconventional oil and gas development.

13.15 In relation to cardiovascular conditions and diabetes, those in the most deprived areas are more likely to have such a condition than those in the least deprived areas (18% and 12% respectively). The same pattern applies to the percentage of adults reported having Chronic Obstructive Pulmonary Disease (COPD), and was recorded for only 2% of adults in the two least deprived quintiles, compared with 7% of those in the most deprived areas. The prevalence of ever experiencing wheezing was also linked to deprivation, with prevalence higher in the most deprived areas (36%) than the least deprived areas (25%)^[269]. Existing health conditions can be exacerbated by poor air quality.

Air quality

13.16 Scotland has seen strong declines in emissions of most pollutants between 1990 and 2013: SO₂ by 87%, NO_x by 67%, PM₁₀ by 53% and PM_2.5 by 56% (UK)^[270].

Water quality

13.17 In recent decades, significant improvements in water quality have been observed in many rivers, canals and estuaries due to decreases in the releases of environmental pollutants. Recent data^[271] shows that 80% of groundwaters in Scotland were at good status in 2016. In addition, 62% of surface waters (rivers, lochs, and estuaries) were at good status or better in 2016^[272]. There has been a steady improvement in the water quality of Scotland’s designated bathing sites since 1988. In 2016, about 80% of Scotland’s designated bathing waters met the sufficient or better classification^[273].

Noise, light, odour

13.18 The Scottish Government has produced noise maps for major roads, rail airports and industry. This data only relates to the four main cities, and for Edinburgh this shows higher noise levels in relation to the main roads and airport^[274]. The pattern of concentration of noise pollution around main roads and areas of industry is likely to be replicated across the central belt. In relation to light pollution, the Central Belt is one the most densely populated parts of Scotland, and again light pollution is higher in towns, cities and along main transport routes.

Seismic activity

13.19 An analysis of recent instrumental recordings of earthquakes and older historical data shows that earthquake activity in Scotland is low. On average there are eight earthquakes with a magnitude of 2.0 M_L or above in Scotland every year. In the last 400 years, only two earthquakes with a magnitude greater than 5.0 M_L have been observed. The largest recorded earthquake in Scotland had a magnitude of 5.2 M_L. Therefore, the risk of damaging earthquakes is low.

13.20 Most of Scotland’s seismic activity is on the west side of mainland Scotland, north of the Highland Boundary Fault. Earthquake activity in the Midland Valley of Scotland is lower, and most of the recorded earthquakes in this area were induced by coal mining. Since the decline of the coal-mining industry in the 1990’s, very few induced earthquakes have been recorded^[275].

Local amenity, mental well-being, access and recreation

13.21 Local environmental quality, access to greenspace and opportunities for access and recreation have been found to contribute widely to public health and wellbeing by promoting physical activity and reducing health inequalities while also promoting mental and social health^[276]. Participation in all physical activity and sport has risen between 2011 and 2016, and is driven by the rise in recreational walking. Around half of adults (48 %) visited the outdoors at least once a week in the last year, however adults living in the most deprived areas were more likely not to have made any visits to the outdoors in the past twelve months (19%) compared to those in the least deprived areas (7%). Most adults (7%) are satisfied or very satisfied with their nearest area of greenspace, a similar proportion to 2015.^[277]

Physical health and safety risks

13.22 Scotland has shown decreasing trends in the number of people killed or seriously injured in road accidents. The total numbers of casualties on Scottish roads has fallen by 1% between 2015 and 2016 and are at their lowest level since records began over 50 years ago. Serious injury casualties fell in every year in the last ten apart from small rises in 2008, 2012 and 2014, while there have been no increases in slight injury casualties.^[278]

13.23 Statistics on work related fatal injuries in Scotland show that after standardising for industry composition, fatality rates in Scotland are not significantly higher than the rate for Great Britain as a whole. Non-fatal injury rates in Scotland are also not statistically significantly different from Great Britain^[279].

What current regulatory processes control these effects?

13.24 The regulatory processes for air and water which also apply to population and human health are set out under the respective topics, and are not replicated in this section.

13.25 At the European level, the REACH Enforcement Regulations 2008^[280] require that all additives in fracturing fluids that exceed the one metric tonne threshold and other requirements set by REACH Regulation must be registered at the European Chemicals Agency by the manufacturer or importer.

13.26 In the UK, there are systems in place to manage the impact of chemical spillage in the event of a traffic accident. These controls would reduce, but not fully eliminate, such risks.

13.27 Any unplanned release of fluids (liquid or gas) from an oil or gas well must be reported to HSE under Schedule 2, Part 1, Section 20 of the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013^[281].

13.28 The Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2017^[282] relate to the assessment of the impact of certain public and private projects on the environment through the planning system. This would require an assessment of the potential risks to human health. For instance, any planning application for unconventional oil and gas development with the potential for generating significant traffic movements could be made subject to an Environmental Impact Assessment (EIA). Traffic modelling studies are likely to be needed in support for an EIA for unconventional oil and gas development. The exception would be cases where the potential traffic impact is too low to warrant such a study^[283].

13.29 The Management of Extractive Waste (Scotland) Regulations 2010^[284] requires that extractive waste will be managed without using processes or methods which could cause a nuisance through noise or odours.

13.30 The Control of Major Accident Hazards Regulations 2015 (COMAH)^[285] seek to prevent major accidents involving dangerous substances and limit the consequences to people and the environment of any accidents which do occur. If COMAH applies, the operator will be required to identify their major hazard scenarios and demonstrate to the Competent Authority that they have taken control measures to prevent major accidents and made arrangements for mitigatory action in the event of an accident occurring. The enforcement authority (HSE and SEPA) can prohibit operation where these measures are seriously deficient.

13.31 Workplace exposure to harmful substances is regulated under the Control of Substances Hazardous to Health Regulations 2002 (COSHH)^[286] by HSE. Under COSHH, assessment and control of the hazard posed by fluids containing chemicals that may be harmful to worker health is required.

13.32 The Ionising Radiations Regulations 1999^[287] may apply to employers working with materials containing NORM depending on if they are used above the specified level.

13.33 The Workplace (Health, Safety and Welfare) Regulations 1992^[288] require every workplace to have suitable and sufficient lighting, ensuring that lighting or lack of it does not present a risk to health and safety. The 1992 Regulations also set out requirements for onsite traffic management to manage the risks from workplace transport effectively. The operator will need to consider three key areas: safe site, safe vehicle, and safe driver.

13.34 The Control of Noise at Work Regulations 2005^[289] set out legislation to control noise exposure and, where necessary, provide hearing protection.

13.35 In the UK, there is also legislation to regulate the noise impacts from industrial activity such as BS 4142: 2014 ‘Methods for Rating and Assessing Industrial and Commercial sound’^[290]. BS 4142 provides a method for rating sound from industrial and commercial sources affecting people inside or outside dwellings or premises used for residential purposes.

13.36 Various phases of unconventional oil and gas development are associated with the use of a large number of chemicals and with the release of a range of environmental emissions. Some of these are known to be hazardous to human health and therefore subject to regulatory health limits for short-term or chronic exposures. These regulations are set by regulatory and other export bodies such as the World Health Organization (WHO).^[291]

13.37 Effects which can be defined as a statutory nuisance are primarily contained within Part III of the Environmental Protection Act 1990, as amended. This includes issues such as odour, artificial light, and noise^[292].

What stages of unconventional oil and gas development result in these effects, and what is the nature of these effects?

13.38 Impacts on air and water are addressed under these topic areas.

Noise impacts

Business as usual – shale oil and gas

13.39 The potential noise impacts associated with unconventional oil and gas site activity and transport flows would occur with immediate effect during the exploration, appraisal and production stage. These stages combined could occur over a period of approximately 30 years for an individual development. The scale of these impacts is likely to be greatest during the production phase. The duration of these effects are temporary, as site activity and transport flows would come to a halt when unconventional oil and gas operations eventually cease. Furthermore, a single passing of a heavy goods vehicle (HGV) is a short duration event.

13.40 A study by Ricardo Energy & Environment^[293] concludes that additional traffic movements associated with unconventional oil and gas developments are unlikely to be significant at a regional or national scale, in view of the much greater number of traffic movements resulting from other activities.

13.41 The noise impacts of drilling associated with hydraulic fracturing are expected to be minimal.

13.42 As mentioned previously, flaring may also be a source of noise. However, evidence suggests that the disruption caused by flaring is minimal – particularly compared to refinery activity or gas compression facility vent relief valves^[294].

13.43 Based on this information, noise impacts associated with unconventional oil and gas operations (caused by traffic and site activities) are expected to be minimal. However, there is inadequate evidence to determine whether unconventional oil and gas-associated noise impacts would occur at levels that could pose a risk to physical health^[295]. The potential noise impacts depend on a number of local factors including existing background noise, proximity to sensitive receptors and potential mitigation measures proposed (e.g. use of acoustically insulated boxes)^[296]. As a result, there is uncertainty whether noise pollution associated with unconventional oil and gas could have significant impacts on human health. Under the KPMG high scenario, cumulative effects from the noise associated with the higher number of pads and wells could have significant negative local effects. Although this is likely to occur within areas with existing higher levels of background noise, and taking the regulatory controls into account, this effect is judged to be minor negative but uncertain. These effects are likely to be lower for the central and low KPMG scenarios.

Business as usual - CBM

13.44 It is important to note that the potential noise impacts associated with CBM are expected to be lower than those associated with hydraulic fracturing. Coal bed methane requires shallower drilling depths and CBM is characterised by a significantly reduced need for imported water, which is likely to require less traffic movements. As a result, CBM operations are expected to generate less noise and/or operate for a shorter period^[297]. Taking these factors and the regulatory controls into account, the effects of CBM on noise are judged to be negligible.

Pilot

13.45 The development of a pilot relates to a single pad and an unknown number of wells. The impacts of noise from traffic and onsite activity such as flaring will be local in their effect and controlled by the regulatory framework. An urban fringe and semi-urban pilot are assumed to be closer to areas of population and any impacts could affect these populations. A rural pilot is assumed not to be located within close proximity to large areas of population and any effect would be further limited by the lower potential number of receptors. The overall impact on noise from a single pilot is judged to be negligible.

Preferred policy position

13.46 The preferred policy position means that adverse noise impacts resulting from shale oil and gas production (greatest for the KPMG high production scenario, and less for the central and low scenarios), CBM production and, to a lesser extent, a pilot development, would be avoided.

13.47 This is considered to be a minor positive effect.

Light pollution

Business as usual – shale oil and gas

13.48 Light pollution associated with unconventional oil and gas site activity would occur with immediate effect during the exploration, appraisal and production stage. These stages combined could occur over a period of approximately 30 years for an individual development. The scale of these impacts is likely to be greatest during the production phase. The duration of these effects are temporary, as the impacts of light pollution decrease as unconventional oil and gas site activity declines towards the end of the production phase.

13.49 The impacts of light pollution can be reduced by scheduling flaring and truck movements to take place during daylight hours, as well as using spotlights that shed light only on the working area^[298].

13.50 According to a recent study by Health Protection Scotland (HPS)^[299], there is inadequate evidence to determine whether unconventional oil and gas-associated light pollution would occur at levels that could pose a risk to physical health. As a result, there is uncertainty regarding whether light pollution with unconventional oil and gas could have significant impacts on human health.

13.51 Under the KPMG high scenario, the scale of shale oil and gas development is larger with a greater number of pads, wells and vehicle movements and higher levels of potential light pollution, although these effects would be temporary. In particular cumulative effects from pads which are developed in proximity to each other could increase the scale of effect. Taking these effects, and the regulatory controls into account, minor negative but uncertain effects are identified for all of KPMG scenarios, reflecting the potential for the distribution to result in cumulative effects.

Business as usual – CBM

13.52 The nature of the light pollution effects described above is similar for both shale oil and gas extraction and CBM, although the effects from transport for an individual pad may be lower where hydraulic fracturing vehicle movements are not required. The development of two pads also limits the overall scale of effect of light pollution, and taking regulatory controls into account, negligible effects are identified.

Pilot project

13.53 Compared to the ‘business as usual’ alternative, the development of a single pilot location limits the area over which these effects may occur. A rural pilot location is likely to have greater local impacts in terms of light pollution due to the rural character of the area, although however the number of potential receptors would be lower. Semi-urban and urban fringe locations would be located closer to larger numbers of receptors, but are also located within locations which are already subject to higher levels of light pollution. The effects of all three pilots are therefore judged to be negligible.

Preferred policy position

13.54 The preferred policy position means that light pollution impacts resulting from shale oil and gas production (greatest for the KPMG high production scenario, and less for the central and low scenarios), CBM production and, to a lesser extent, a pilot development, would be avoided.

13.55 This is considered to be a minor positive effect.

Odour nuisance

Business as usual – shale oil and gas

13.56 Odour nuisance associated with unconventional oil and gas site activity would occur with immediate effect during the exploration, appraisal and production stage. These stages combined could occur over a period of approximately 30 years for an individual development. The scale of these impacts is likely to be greatest during the production phase. The duration of these effects are temporary, as the impacts of odour nuisance decrease as unconventional oil and gas site activity declines towards the end of the production phase.

13.57 A recent report by Health Protection Scotland ^[300] states that there is inadequate evidence to suggest that odour nuisance associated with unconventional oil and gas developments could pose a risk to human health. There is also regulatory control of odour nuisance, however odour nuisance associated with unconventional oil and gas developments are uncertain.

Business as usual – CBM

13.58 It is uncertain if odour issues associated with CBM differ from odour issues associated with shale oil and gas extraction. Therefore the effects of odour are uncertain.

Pilot project

13.59 The development of a pilot project would have local impacts from any resulting odour issues. Semi-urban and urban fringe pilots would be located closer to larger numbers of receptors than a rural pilot location.

13.60 As noted above odour nuisance is uncertain, however based on the limited scale of any potential effect uncertain negligible effects for all three pilot locations are identified.

Preferred policy position

13.61 The preferred policy position would result in the avoidance of uncertain effects associated with odour on human health.

Felt seismic activity

Business as usual – shale oil and gas

13.62 Induced seismic activity resulting from unconventional oil and gas developments are likely to be greatest during the production phase, which for an individual development is likely to occur over a period of approximately 15 years. In the early stages of exploration and appraisal, there may not be enough data to carry out efficient fracturing operations – increasing the risk of felt seismic activity occurring in subsequent stages^[301]. The effects of disturbance are judged to be temporary due to the instantaneous nature of seismic events. However, it is recognised that induced seismicity is often the result of long-term unconventional oil and gas production.

13.63 It is judged that unconventional oil and gas induced seismicity would be more likely to occur in major faults of the Midland Valley, given their geological sensitivity. It is important to note that the BGS regional data cannot provide an accurate representation of the complexity of structures within the subsurface due to their large scale^[302], and there is uncertainty associated with the location or potential occurrence of seismic events.

13.64 A study by the Royal Society and Royal Academy of Engineering (2012)^[303] concluded that health, safety and environmental risks associated with hydraulic fracturing, including impacts on aquifers and seismicity, can be managed effectively in the UK– provided best practices are implemented and enforced through regulation.

13.65 Taking the evidence above into account, it is judged that disturbance caused by induced seismic activity would be minimal. Under the KPMG scenarios the high scenario involves 31 pads with 30 wells per pad, which would result in hydraulic fracturing across a wider area. Based on the evidence outlined above it is judged that impacts on human health from seismic activity are minor negative uncertain. These effects are likely to be lower for the central and low KPMG scenarios.

Business as usual – CBM

13.66 CBM may be extracted through dewatering, with or without hydraulic fracturing, depending on local geological conditions (though currently it is usually extracted without the use of hydraulic fracturing). Assuming that hydraulic fracturing is the main cause of seismic activity, the impacts from CBM development are judged to be negligible.

Pilot project

13.67 Any seismic activity associated with the development of a single pilot with an unknown number of wells is anticipated to have a local effect. Urban fringe and semi-urban pilots would be closer to areas of population and any impacts could affect these populations. A rural pilot would not be located within close proximity to large areas of population and any effect would be further limited by the lower potential number of receptors. For all three hypothetical pilot location effects on human health are judged to be negligible.

Preferred policy position

13.68 The preferred policy position means that adverse impacts on human health from induced seismic activity associated with shale oil and gas production (greatest for the KPMG high production scenario, and less for the central and low scenarios), CBM production and, to a lesser extent, a pilot development, would be avoided.

13.69 This is considered to be a minor positive effect.

Impacts on local amenity and mental well-being, and access to opportunities for recreation and physical activity.

Business as usual – shale oil and gas

13.70 The development of a pad is assumed to exclude the use of land for other purposes such access and recreation. Therefore if land was currently used for access or recreation the development of unconventional oil and gas could preclude this use. It is assumed that alternative route creation or access provision would be required through the planning process, however the size of the pad development and impact on local access networks could reduce connectivity between communities, with adverse effects on population and human health. This extends over the operational period of the pad through to the completion of decommissioning, a period of approximately 30 years. This effect would be temporary, reflecting the restoration of the site following decommissioning.

13.71 Under the KPMG high scenario, the scale of development would result in the largest area of land affected by unconventional oil and gas development with potential negative effects on local access and recreation. A secondary effect would be the adverse effects on environmental quality and industrialisation of the landscape reducing the quality of recreational experience. The potential cumulative effects of pads within the same area could increase the scale of effects on local access and recreation opportunities, however this effect is uncertain as the location of pads is unknown. Due to the uncertainty over the location of pads, and the potential for cumulative effects, the scale of effect under all of the KPMG scenarios is judged to be minor negative, but uncertain.

Business as usual – CBM

13.72 The nature of the effects described above is similar for both shale oil and gas extraction and CBM. The scale of development of CBM is anticipated to involve two pads and is therefore lower in terms of cumulative impacts on access and recreation. Impacts could be locally significant, a minor negative but uncertain effect is identified.

Pilot

13.73 The development of a pilot project is assumed to involve the development of a single pad and an unknown number of wells. The location of a pilot is unknown, however it is assumed that a rural pilot would be located in an area with lower population, and there could be greater opportunities for mitigation of these environmental effects, and a negligible effect is identified. A semi urban pilot and urban fringe pilot area may have greater importance for recreation, opportunities for mitigation may be more limited due to built development and effects could be locally significant. A minor negative but uncertain effect is identified.

Preferred policy position

13.74 The preferred policy position means that adverse impacts on opportunities for access and recreation resulting from shale oil and gas production (greatest for the KPMG high production scenario, and less for the central and low scenarios), CBM production and, to a lesser extent, a pilot development, would be avoided.

13.75 This is considered to be a minor positive effect.

Physical health and safety risks

Business as usual – shale oil and gas

13.76 As discussed previously, explosive risk associated with methane emissions from wells is a health and safety concern. High concentrations of methane (generally identified as making up more than 5% of the mix) mixed with air can be flammable or explosive in the presence of an ignition source. This could present a serious health and safety risk to the workforce. A recent study by the Health Protection Scotland ^[304] has established that waterborne methane associated with unconventional oil and gas development occur at levels that could pose a potential explosive risk. As a result, careful monitoring of wellhead areas with automated sensors is common practice as it is a requirement by the Health and Safety Executive (HSE) which is expected to minimise explosive risks associated with unconventional oil and gas operations^[305].

13.77 The study by Health Protection Scotland also found that there is sufficient evidence to suggest that respirable crystalline silica, a component of fluids used in hydraulic fracturing processes, occurred at levels that could pose a risk to unconventional oil and gas workers’ health. However, there is limited evidence to suggest that respirable crystalline silica could pose a risk to the health of nearby residents due to methodological weaknesses in original studies. Therefore, there is some uncertainty as to the extent to which crystalline silica could pose a risk to the health of nearby residents.

13.78 Physical health and safety risks would occur with immediate effect during the exploration, appraisal and production stage. These stages combined could occur over a period of approximately 30 years for an individual development. The scale of these impacts is likely to be greatest during the production phase. The duration of when these effects may occur is judged to be temporary, although the effects on the health of individuals could be permanent.

13.79 Under the KPMG scenarios the scale of development under the high scenario means that the total number of workers and residents exposed to health and safety risks is greater than under the central and low scenarios. There is also a degree of uncertainty over some of the risks. The role of regulatory control is recognised, however significant negative but uncertain effects are identified. These effects are likely to be lower for the central and low KPMG scenarios.

Business as usual – CBM

13.80 The evidence base on CBM is more limited than that on shale oil and gas. The report by HPS Scotland concluded that the nature of hazards associated with CBM activities is very similar to those from shale-sourced unconventional oil and gas^[306]. It is noted that risks associated with respirable crystalline silica would not occur where hydraulic fracturing does not take place. The scale of CBM development is assumed to be two pads and therefore the extent of health and safety risks is more limited than development of shale oil and gas. Although controlled by regulation, the nature of potential health and safety risks means that significant negative but uncertain effects are identified.

Pilot project

13.81 The development of a pilot project has the potential for health and safety impacts for workers and for residents. The nature of the risk to receptors is the same as for the ‘business as usual’ alternative. However, compared to the ‘business as usual’ alternative, the development of a single pilot location relates to a limited area over which these effects may occur, with a smaller number of potential receptors. The number of potential residential receptors to health and safety risks is lowest for a rural pilot location, and greater for semi-urban and urban fringe locations.

13.82 The scale of effects relate to the development of a single pad. However, as described for CBM, the nature of potential health and safety risks means that significant negative but uncertain effects are identified.

Preferred policy position

13.83 The preferred policy position means that adverse health and safety impacts resulting from shale oil and gas production (greatest for the KPMG high production scenario, and less for the central and low scenarios), CBM production and, to a lesser extent, a pilot development, would be avoided.

13.84 This is considered to be a significant positive effect.

Road accidents

Business as usual – shale oil and gas

13.85 Recent evidence has shown that a number of regions in the United States have reported increases in the rates of road accidents in recent years, correlating with the expansion of the shale gas industry. Current legislation in Scotland is expected to result in increased seatbelt use for commercial vehicle operators – potentially minimising the rate of work-related motor vehicle-related deaths^[307].

13.86 The increased risk of road accidents associated with unconventional oil and gas site activity and transport flows would occur with immediate effect during the exploration, appraisal and production stage. These stages combined could occur over a period of approximately 30 years for an individual development. The scale of these impacts is likely to be greatest during the production phase, when traffic movements are required to support unconventional oil and gas operations. The duration of these effects are temporary, as the risk of road accidents would decrease with declining vehicle movements as the production phase ends. However the effect of any road accidents on the individuals involved could be permanent.

13.87 If pads are developed in close proximity to each other, cumulative effects on local roads could occur. However the location of developments is uncertain under all of the KPMG scenarios. Under the KPMG high scenario the level of road traffic movements would be greatest, reflecting the higher number of pads and wells. Cumulatively the high scenario also leads to the greatest overall increase in traffic. As the distribution of pads is unknown locally significant impacts under any of the three KPMG scenarios could occur and minor negative but uncertain effects are identified.

Business as usual – CBM

13.88 Ricardo Energy and Environment (2016) found that the range of unconventional oil and gas development scenarios considered could give rise to between 210 and 1,670 traffic movements per week on average across the country as a whole, with a further 99 movements associated with the coal bed methane scenario^[308]. The scale of CBM development, and the potential for lower water requirements and associated vehicle movements, means that negligible but uncertain effects are identified for impacts on road safety.

Pilot project

13.89 The development of a pilot project is assumed to involve the development of a single pad and an unknown number of wells with the level of traffic movements associated with a single pad. The location of a pilot is unknown, however the development of semi urban and urban fringe pilots have the potential for greater impacts on road safety due to their proximity to communities. Conversely such locations may also provide greater access to the main road network, reducing direct impacts on local communities in terms of road safety. Negligible but uncertain effects are identified for road safety for all three pilot locations.

Preferred policy position

13.90 The preferred policy position means that adverse impacts on road safety resulting from shale oil and gas production (greatest for the KPMG high production scenario, and less for the central and low scenarios), CBM production and, to a lesser extent, a pilot development, would be avoided.

13.91 This is considered to be a minor positive effect.

Cumulative, synergistic and secondary effects

Business as usual – shale oil and gas extraction

13.92 Impacts on health potentially arise from a number of activities associated with unconventional oil and gas development, and result in impacts on several different aspects of health and wellbeing.

13.93 The scale of effects that arise is likely to be most significant under the KPMG high scenario for shale oil and gas extraction, which has the highest number of pads and greatest number of wells developed per pad. This scenario could result in the greatest magnitude of effects, and also impacts on the great number of individuals and communities. Where unconventional oil and gas developments occur in closer proximity to each other, this also means that some communities may experience impacts from several different developments, with potential cumulative effects. However the location of pad developments is uncertain.

13.94 Reflecting the potential scale of development under the KPMG scenarios, significant negative but uncertain cumulative effects are identified for population and human health.

13.95 Environmental regulation plays a key role in reducing the overall risks to health for a number of impacts on health, particularly air and water pollution. However there may be inadequacies in the current regulatory framework for managing some risks to health linked to unconventional oil and gas development^[309].

Business as usual – CBM, Pilot Project

13.96 The development of CBM alone or a single pilot project would not result in significant cumulative effects.

Preferred policy position

13.97 The preferred policy position means that pressures on population and human health resulting from unconventional oil and gas development, in addition to the existing pressures on population and human health, would be avoided.

The timeframe for the avoidance of these additional effects is approximately the next 40 years reflecting the timescale of unconventional oil and gas development described in the KPMG scenarios. The avoidance of these effects is judged to be permanent within the context of the SEA. The scale of avoidance of effects reflects the geographic area identified as prospective for shale oil and gas, across the Central Belt of Scotland.

13.98 The preferred policy position means that cumulative adverse impacts on population and human health, resulting from shale oil and gas production (greatest for the KPMG high production scenario, and less for the central and low scenarios), CBM production and, to a lesser extent, a pilot development, would be avoided. This is considered to be a significant positive effect.

Scope for further mitigation

13.99 The assessment results are based on the application of existing regulatory controls. The evidence base includes information on a number of processes which could be implemented to reduce the scale of impact on population and human health. These could reduce the overall potential scale of effect from unconventional oil and gas development, and therefore the associated scale of effect avoided as a consequence of the preferred policy position.

13.100 The applicability and practicality of many of these additional measures will be determined at a site specific level so it is not possible to draw firm conclusions as to the extent to which they would mitigate predicted effects successfully. Potential measures include:

13.101 Noise and light pollution– noise surveys could be carried out to establish whether noise exposure associated with unconventional oil and gas developments is likely to be hazardous. Noise impacts associated with traffic movements could be reduced if areas with a high density of sensitive receptors would be avoided, if possible. Furthermore, potential noise impacts could also be reduced through undertaking regular maintenance of equipment, the use of silencers or other noise attenuation equipment, the use of enclosures on noise generating equipment associated with drilling, minimising night-time vehicle movements, and minimising the use of audible vehicle reversing alarms at night. In addition, positioning and rotating the rig could help to mitigate drilling noise, as well as light nuisance.

13.102 Odour nuisance– nuisance caused by odour issues could be reduced through a number of mitigation measures. Examples include the disclosure and risk assessment of fracturing fluid chemicals and environmental monitoring (baseline and ongoing).

13.103 Health issues associated with induced seismic activity – contingency planning to deal with the impacts of induced seismic activity on human health could be used to reduce potential impacts.

13.104 Impacts on local amenity and mental well-being – screening of site activities through planting could help to reduce impacts on local amenity associated with unconventional oil and gas developments.

13.105 Physical health and safety risks – contingency planning to deal with the impacts of unexpected events and hazards could be used to reduce potential impacts.

13.106 Road accidents – the occurrence of road accidents associated with unconventional oil and gas development could be reduced if areas with a high density of sensitive receptors would be avoided, if possible. Additional safety measures are likely to further reduce the occurrence of road accidents. Examples of such measures include improving site access and junction design, signing, lining and providing anti-skid treatment^[310].

Health impacts associated with air and water pollution – many of the water, soil and air mitigation measures could help to protect public health. These include careful soil stripping and restoration, the use of geotextiles and geo-synthetics, the use of biodegradable fracking fluids, the (optimised) treatment of flowback and produced water through mobile units or at central facilities, the use of advanced monitoring technologies (e.g. DTS and DAS), annual inspections and repair, the use of supply chain management and ICT resources, and the re-use of wastewater.

Table 13.1: Summary of effects on population and human health

Environmental impact	Alternative	Potential scale of development	Timescale when effect may occur	Duration of effect	Predicted effect taking account of existing regulation	Key areas of uncertainty
Noise	Business as usual – shale oil and gas extraction	Major	Short to long term	Temporary	A minor negative effect is identified reflecting potential noise impacts.	Noise impacts depend on a number of local factors and uncertainty over whether noise pollution associated with unconventional oil and gas could have significant impacts on human health.
	Business as usual – coal bed methane extraction	Minor	Short to long term	Temporary	A negligible effect is identified as potential noise impacts associated with CBM are expected to be lower than those associated with hydraulic fracturing for shale oil and gas.
	Pilot project	Minor	Short to long term	Temporary	A negligible effect is identified as potential noise impacts associated with a single pad are local in effect.
		Preferred policy position	None	Short to long term	Permanent	A minor positive effect is identified reflecting the avoidance of minor negative effects.
Light pollution	Business as usual – shale oil and gas extraction	Major	Short to long term	Temporary	A minor negative effect is identified for all of the KPMG scenarios, reflecting the potential for the distribution of development to result in cumulative effects.	There is inadequate evidence to determine whether unconventional oil and gas-associated light pollution would occur at levels that could pose a risk to physical health
	Business as usual – coal bed methane extraction	Minor	Short to long term	Temporary	A negligible effect is identified as the scale of development limits the overall effect of light pollution.
	Pilot project	Minor	Short to long term	Temporary	A negligible effect is identified as the scale of development limits the overall effect of light pollution.
	Preferred policy position	None	Short to long term	Permanent	A minor positive effect is identified reflecting the avoidance of minor negative effects.
Odour nuisance	Business as usual – shale oil and gas extraction	Major	Short to long term	Temporary	Odour nuisance associated with unconventional oil and gas developments are uncertain.	There is inadequate evidence to suggest that odour nuisance associated with unconventional oil and gas developments could pose a risk to human health.
	Business as usual – coal bed methane extraction	Minor	Short to long term	Temporary
	Pilot project	Minor	Short to long term	Temporary
	Preferred policy position	None	Short to long term	Permanent	The avoidance of uncertain effects associated with odour on human health.
Felt seismic activity	Business as usual – shale oil and gas extraction	Major	Short to medium term	Temporary	A minor negative effect is identified under the KPMG high scenario, reflecting hydraulic fracturing over a wider area, however effects are likely to be lower for the central and low KPMG scenarios.	Location and occurrence of potential seismic events.
	Business as usual – coal bed methane extraction	Minor	Short to medium term	Temporary	A negligible effect is identified as CBM is usually extracted without hydraulic fracturing.
	Pilot project	Minor	Short term	Temporary	A negligible effect is identified reflecting the limited scale of effect from a single pilot.
	Preferred policy position	None	Short to long term	Permanent	A minor positive effect is identified reflecting the avoidance of minor negative effects.
Amenity, mental wellbeing, recreation and physical activity	Business as usual – shale oil and gas extraction	Major	Short to long term	Temporary	A minor negative effect is identified reflecting potential loss of land for access and recreation, impacts on environmental quality.	The location of pads and potential impacts on recreational resources.
	Business as usual – coal bed methane extraction	Minor	Short to long term	Temporary	A minor negative effect is identified reflecting potential locally significant effects.
	Pilot project	Minor	Short to long term	Temporary	A minor negative effect is identified reflecting potential locally significant effects for the semi urban and urban fringe pilots.
	Preferred policy position	None	Short to long term	Permanent	A minor positive effect is identified reflecting the avoidance of minor negative effects.
Physical health and safety	Business as usual – shale oil and gas extraction	Major	Short to long term	Temporary and permanent	A significant negative effect is identified reflecting the physical health and safety risks.	Waterborne methane poses a potential explosive risk. The extent to which crystalline silica could pose a risk to the health of nearby residents.
	Business as usual – coal bed methane extraction	Minor	Short to long term	Temporary and permanent	A significant negative effect is identified reflecting the physical health and safety risks.	Limited evidence base on risks to physical health and safety for CBM.
	Pilot project	Minor	Short to long term	Temporary	A significant negative effect is identified reflecting the physical health and safety risks, although it is recognised that there is a smaller number of potential receptors.
	Preferred policy position	None	Short to long term	Permanent	A significant positive effect is identified reflecting the avoidance of significant negative effects.
Road accidents	Business as usual – shale oil and gas extraction	Major	Short to medium term	Temporary and permanent	A minor negative effect is identified reflecting the effect of increased traffic movements and the impact on road accident risk.	The location of developments and proximity to each other and the potential for cumulative effects on road safety.
	Business as usual – coal bed methane extraction	Minor	Short to medium term	Temporary	A negligible effect is identified reflecting the lower level of traffic movements.	Potentially lower vehicle movements, if hydraulic fracturing is not required.
	Pilot project	Minor	Short term	Temporary	A negligible effect is identified reflecting the lower level of traffic movements.	Location in semi urban and urban fringe areas could have greater impacts on road safety due to their proximity to communities, or conversely could have better access to the main road network.
	Preferred policy position	None	Short to long term	Permanent	A minor positive effect is identified reflecting the avoidance of minor negative effects.
Cumulative	Business as usual – shale oil and gas extraction	Major	Short to long term	Temporary	A significant negative effect is identified reflecting the range of impacts on health and impacts on different aspects of health and wellbeing and the scale of development.	The location of unconventional oil and gas developments in close proximity to each other would lead to greater cumulative effects.
	Business as usual – coal bed methane extraction	Minor	Short to long term	Temporary	No cumulative effects identified.
	Pilot project	Minor	Short to long term	Temporary	No cumulative effects identified.
	Preferred policy position	None	Short to long term	Permanent	A significant positive effect is identified reflecting the avoidance of significant negative effects.