TECHNIQUE

Burning of Carcasses for Foot-and-Mouth Disease (Disease Investigation & Control - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Control / Treatment & Care / Techniques:
Synonyms and Keywords
  • Cremation of carcasses
  • Alternative to burial
Description Carcasses are sprayed with disinfectant immediately after slaughter (D37.Para128)

Carcasses are placed on a pyre of appropriate fuel and burned thoroughly:

  • A flat piece of ground is chosen, close to the point of slaughter.
  • The pyre is built using appropriate materials, in sufficient quantities.
  • Carcasses are placed on top of the fuel, in a single layer.
  • Carcasses are soaked in diesel oil or paraffin.
  • The pyre is lit.
  • Once burning of carcasses is complete, the remaining ash is buried in an appropriate pit.
Appropriate Use (?)
  • Burial has often been the preferred means of disposal for foot-and-mouth disease carcasses where possible, with burning considered as the next choice.
  • Burning may be appropriate when burying is not possible due to:
    • High water table
    • Insufficient space
    • Inappropriate soil conditions (e.g. only thin layer of soil over solid rock)
    • Danger of carcasses contaminating water supplies.
  • Can be done on-site.
  • No risk of pollution of ground water
  • Can dispose of relatively large numbers of animals
(D37.Para128, D37.Para130, W18.Apl01.sib1)

Note: In the UK, advice from the Environment Agency following the 2001 FMD epidemic, to the Royal Society Infectious Diseases in Livestock Inquiry was a preference for, in order, rendering; commercial incineration; disposal in licensed landfill sites; on-site burning; and on-site burial. This order was based on both risk to the environment and risks to human health. (Infectious Diseases in Livestock [Royal Society Inquiry Report] B495.9.w9 - full text provided)

Notes
  • Virus may remain viable on carcasses and in carcasses (except where the pH drops e.g. in muscles) for prolonged periods after slaughter.
  • The aim in carcass disposal is to minimise the possibility of further spread of disease from the carcasses (W18.Apl01.sib1).
  • It is important to keep the fire contained and to get sufficient air movement under the carcasses to maintain a hot fire and completely burn the carcasses.
  • Wood, coal, fuel oil, napalm, and other fuels have been successfully used for burning carcasses of animals in disease control operations (B36.4.w4: Chapter 4 Disease Control Operations).
  • Waiting 10-15 minutes after covering the carcasses with paraffin or similar before lighting the pyre may facilitate burning (B36.4.w4: Chapter 4 Disease Control Operations).
  • The heat generated by large-scale carcass burning operations is intense enough to cause metal pipes to bend.
    • It is important to construct a support surface sufficiently sturdy that it does not collapse into the fire.
    • When cinder blocks are used to support burning platforms, the length of the platform should be extended to keep the blocks out of direct heat or they will soon crumble.
    • (B36.4.w4: Chapter 4 Disease Control Operations).
  • During dry weather, burning carcasses in a pit surrounded by a vegetation-free area is more desirable than above-ground burning. (B36.4.w4: Chapter 4 Disease Control Operations).
  • Hay, feedstuffs, bedding etc. from an Infected Premises which cannot be adequately disinfected may be burned with the carcasses (D37.Para136, J3.102.w7).
  • It has been suggested that the use of napalm may shorten the time required for the disposal of carcasses by burning, and also decrease the total quantity and cost of fuel required.
    • Modern napalm mixtures have been used successfully for the rapid disposal of livestock carcasses, for example in anthrax disease control operations. (W27.24Mar01.sib2)
    • "Recent burns in Nevada show that by using domestic napalm cow carcass can be 100% incinerated on-site in 60 minutes, a procedure markedly cheaper and faster than using wood and rubber tires; carcass incineration with wood will take 1-3 days." (W27.14Feb01.sib3)
Complications/ Limitations / Risk
  • Preparation of a traditional pyre takes a considerable length of time, much longer than digging of a burial pit.
    • "At least a day is required to prepare a pyre for 100 head of cattle" (D37.Para128).
    • Increased time to completion of disposal adds to total risk of virus dissemination.
  • Time taken to burn carcasses thoroughly takes time.
    • "two days are then necessary to complete burning" (D37.Para128).
    • Delays add to the risk of infection spreading from carcasses, even if these are sprayed with disinfectant immediately after slaughter (D37.Para128).
  • Risk of transport of virus on rising air (thermal air currents) without being heated sufficiently for virus destruction, particularly with inefficient burning. (J18.49.w1, D37.Para128)
    • Studies carried out during the 2001 FMD epidemic in the UK indicate that FMD virus is not likely to be dispersed from pyres. Infection did occur on premises under plumes from the pyres, at dates indicating a possible link, but the models suggested that the concentrations of virus in the plumes as they passed over these premises were insufficient for probable infection, and it was unlikely the pyres were the sources of infection (J3.148.w3, J3.151.w6, J3.154.w3).
  • If carcasses are piled incorrectly on top of one another rather than in a single layer, carcasses in the centre may be protected and not burn properly (B36.4.w4: Chapter 4 Disease Control Operations).
  • Petrol (gasoline) should never be used to encourage burning of carcasses, as it is too hazardous (B36.4.w4: Chapter 4 Disease Control Operations).
  • Air pollution with products of burning carcasses and other materials: e.g. dioxins, hydrocarbons, "which could cause health problems if taken in at high levels over long periods of time" (W32.Apl01.sib1).
    • Dioxins may also be taken up by animals, including fish, from their food and from soil etc. consumed while feeding, and concentrated in their fat (W32.Apl01.sib1)
  • Aesthetically unpleasant
  • Pit required for burial of remains following burning
  • Risk of bovine spongiform encephalopathy (BSE) from carcasses (W32.Apl01.sib1):
    • Increased risk if incomplete burning occurs; 10-fold reduction in infectivity following burning suggested (W32.Apl01.sib1).
    • Risk from ash spilled between burning and burial in ash pit contaminating ground water (assumed 1% of total ash).
    • Risk of rainwater flowing through pit and picking up infectivity (suggested unlikely to be dissolved in water and carried away as the prion is hydrophobic and tends to be attached to solids).(W32.Apl01.sib1)
    • Risk from particles drawn up in combustion plume and dispersed over the surrounding area.(W32.Apl01.sib1)
      • May be inhaled directly
      • May fall onto crops which are then eaten without processing or washing, and ingested.
      • May fall on surface water and enter the water.
      • May fall onto land and infiltrate into ground water or run off into surface water.
    • Total dose likely to received by any one person calculated to be extremely small (W32.Apl01.sib1)
  • Further information on the risks of BSE associated with carcass disposal is given in: Environment Agency: Risks From BSE Via Environmental Pathways (W39.04Jun01.sib1)
  • The requirements for burial of ash other than on-farm in England and Wales have been set out by the Environment Agency Environment Agency: Guidance on ash disposal arising from Pyres and mobile incinerators (W39.31May01.sib1)
  • Note: In the UK, advice from the Environment Agency following the 2001 FMD epidemic, to the Royal Society Infectious Diseases in Livestock Inquiry was a preference for, in order, rendering; commercial incineration; disposal in licensed landfill sites; on-site burning; and on-site burial. This order was based on both risk to the environment and risks to human health. (Infectious Diseases in Livestock [Royal Society Inquiry Report] B495.9.w9 - full text provided)
  • The Lessons Learned Inquiry Report suggested that mass pyres should not be used in future for disposal. (B494.5.w5 - full text provided)
Equipment / Chemicals required and Suppliers
  • The amount of fuel required for one adult bovine (or four adult pigs or three adult sheep) is recommended as follows:
    • One piece of heavy timber, about 3 by 0.3 by 0.3 metres (e.g. a wooden railway sleeper)
    • Coal, 203 kg per bovine carcass (less required per carcass when large number of carcasses).
    • Straw, one bale per bovine carcass.
    • Kindling wood, equal weight to coal.
    • Exothermic (heat-generating) powder, 25 kg per tonne of coal (about 0.8 kg per bovine carcass).
    (W18.Apl01.sib1)
Expertise level / Ease of Use
  • Knowledge of the correct fuel requirements and construction technique is important if efficient burning is to occur.
  • Good handling of carcasses is important to reduce contamination of the environment with virus.
Cost/ Availability
  • Cost of materials for burning may be considerable.
  • Cost of labour and machinery for building a pyre and moving carcasses into position etc. may be considerable.
  • Availability of materials is likely to vary considerable depending on factors such as geographical location and the local and total number of animals which must be disposed of in an outbreak.
Legal and Ethical Considerations
  • May be risk of spread of virus from pyre (J18.49.w1, D37.Para128).
  • Permission must be obtained from the appropriate local authority.
    • Permission is unlikely to be granted where there is high population density, or in a location (e.g. near a main road) where smoke may be hazardous.
    • (W18.Apl01.sib1).
  • Legal restrictions may be based on human or animal health considerations.
  • It is important to consider the possible environmental consequences, such as air pollution, of burning carcasses, particularly large numbers of carcasses.
  • Legal injunctions may be brought against this method of carcass disposal in a given site.
Author Debra Bourne
Referee Suzanne I Boardman
References J3.102.w7, J3.148.w3, J3.151.w6, J3.154.w3, J18.49.w1, (B36.4.w4: Full text available), Infectious Diseases in Livestock [Royal Society Inquiry Report] B495.9.w9 - full text provided, D37.Para54, D37.Para128, D37.Para130, D37.Para136, W18.Apl01.sib1, W27.14Feb01.sib3, W27.24Mar01.sib2, W32.Apl01.sib1, Environment Agency: Guidance on ash disposal arising from Pyres and mobile incinerators (W39.31May01.sib1), Environment Agency: Risks From BSE Via Environmental Pathways (W39.04Jun01.sib1)

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