Health risks

The primary health risks from open-windrow composting are due to bioaerosols.

Bioaerosols consist of organic dust, fungal spores and bacteria which can seriously damage human and animal health – and even kill.

To successfully operate any commercial composting site, from an Exempt License upwards, requires a rigorous and careful approach. However, even with best practice, harmful bacteria and fungi spores are produced and released into the air, resulting in human/animal health problems.

Current Environment Agency policy

For Exempt sites, the EA used to take the position that:

‘there will be a presumption against permitting (and to object to any application) of any new composting process (or modification to an existing process) where the boundary of the facility is within 250 m of a workplace or the boundary of a dwelling, unless the application is accompanied by a site-specific risk assessment, based on clear, independent scientific evidence which show that the bio-aerosol levels are and can be maintained at appropriate levels at the dwelling or workplace.’

The Geissen study, alonside more recent German studies, and research carried out at Sheffield University, brings into question this 250m limit (see Michael Clapham Statement in Parliament in 2007,

Following the Geissen study most states in Germany now adopt a 300-500m safe distance depending on the size of the site. Austria and Denmark have also adopted 500m safe limits.

In Nov ’07 the EA produced guidance 405-07(see revised EA policy) that removed their responsibility for objecting to planning applications but maintained the 250m buffer zone.

In Nov 2010 the EA published new interim guidance ‘composting and potential health effects from bioaerosols‘. This precludes the issuing of NEW permits for commercial open windrow composting when there are sensitive receptors within 250m. For existing sites in this category the EA is rolling out the requirement to undertake bioaerosol monitoring on a quarterly basis. Although we support this in principle we have major concerns about how this is being conducted (see bioaerosol monitoring below)

In terms of bioaerosol assessments (looking at the risks proir to operations) rather than monitoring after the event, it is our experience that the EA are now asking for more reports AFTER planning consent is given. This means the EA are expecting Councillors to make decisions on planning applications without the benefit of such reports and all further documentation is carried out behind closed doors. We recommend you use the Environment Impact Assessment legislation to fight this (see relevant section of this web -site).

Much of the research that has been carried out on these harmful bacteria and fungi has centred on healthy males wearing protective equipment who tend to operate these sites; not females, not children and not animals.

Our MP, Steve Webb, has specifically asked the Government about the research carried out and it has been confirmed there is none (see Parliamentary questions).

The Nov Guidance changes the ‘acceptable’ levels of bioaerosols to the EA have now at least stipulated what levels of bioaerosols they regard as ‘unsafe’:

  • 1,000 cfum3 (total bacteria)
  • 300 cfum3 (gram-negative bacteria)
  • 500 cfum3 (Aspergillus Fumigatus)

Whether these truly are safe levels is hard to say.

The facts about the 250m limit

It seems that the EA’s studies on the ‘safe distance’ for bioaerosols have all been carried out in the flat topography of Norfolk. In hilly areas the bioaerosols do not ‘clump’ together and can therfore travel much greater distances.

The Geissen study, alonside more recent German studies, and research carried out at Sheffield University, brings into question the 250m limit (see Michael Clapham Statement in Parliament in 2007,

The HSE have recognised the additional problems when compost sites are located on top of a hill (see letter from Dr Brian Crook to residents of Stourbridge.)

Following the Geissen study most states in Germany now adopt a 300-500m safe distance depending on the size of the site. Austria and Denmark have also adopted 500m safe limits.

New ‘source data’ (ie which bioaerosols and the quantity of bioaerosols produced by a typical open windrow composting site) have recently been published by the EA in association with Cranfield University. When some of the top experts in the country are putting these numbers into quantitative assessments for clients using dispersion modelling techniques, these are showing that, bioaerosols do not seem to fall to background levels until distances of 700-900m away from the sites are reached. This is in line with the fluid dynamics modelling carried out recently at Sheffield University.

Although we are yet to see the paperwork, we are advised verbally that Bedforshire County Council and the local EA have agreed sites must be at least 350m away from sensitive receptors as a result of all the problems that stemmed from a facility in Haynes. Interestingly Baroness Young lives in Bedfordshire and was reviewing this paperwork as Joan Ruddock was stating in Parliament that there was no problem with the 250m limit!

So, all in all, behind the scenes the EA are under a fair amount of pressure on the 250m limit but at the moment they are sticking doggedly with it. To adopt a different limit of say 500m and close down all the sites within this limit would,of course cost the EA a fortune because they could be sued by each and every operator for any lost profits.

So we believe, in spite of the evidence of cases of ill health, notably cases of aspergilliosis at three different sites, the EA are not going to give up the 250m easily, in fact we believe it will take a court case to change things.

Bioaerosol monitoring

Whilst we support the principle of bioaerosol monitoring by operators we are extremely concerned about the following:

  • A failure to agree an appropriate protocol for determining exactly which bioaerosols should be detected and which methodology for obtaining accurate results should be used.
  • EA officers in most regions are advising that unannounced testing cannot take place, yet at the Bryn site in Gelligaer, Wales the EA are insisting that consultants do just this.Without unannounced testing the operator can improve bioaerosol monitoring results by eg damping down windrows, carrying out activities which tend to result in less bioaerosols, turn finished compost rather than active compost etc.
  • Testing is being carried out when wind conditions make it obvious that there is no risk to sensitive receptors on that day. There are always going to be days when the residents are not exposed to bioaerosols. Surely the authorities should be interested in those days when a problem is much more likely?
  • Consultants are being deliberately obscurant when describing activity at the site.
  • We do not believe there is any mechanism in place to ensure unfavourable results are actually supplied to the regulator. Wouldn’t an operator simply repeat the testing under more favourable conditions?
  • Only local officers with little or no expertise are reviewing the bioaerosol reports.

False reassurance is being claimed from reports when it is clear that either very little activity or lower bioaerosol generating activities have been taking place on the site.

In other words BEWARE of bioaerosol monitoing reports. Read them very carefully to see what they aren’t telling you as well as what they are telling you. Remember is is not unusual for figures of >100,000 cfus to be recorded at 5-10m away from a site. If figures at this distance are always low, someone is trying to pull the wool over your eyes.

What information should you expect the EA to demand before an Exemption/permit is granted?

For all sites, the key control which the EA have relied on seems to be the 250m limit.

Within this buffer zone you would expect the EA to demand a much higher level of risk data to be provided. Unfortunately this has not been the case and there are numerous compost sites causing problems which have been allowed to be located when there are occupied dwellings within the all important 250m zone. Under the new Nov 2010 legislation no new permits will be issued for open windrow sites OR non fully enclosed sites if there are sensitive receptors are within the 250m. Make you measurements VERY carefully.

For sites operating under the new Standard Permits (those which intend to take in 5,000 tonnes or more of green waste material) one of the key conditions always precluded activity from being located within 250 m of occupied dwelling and continue to do so. If operators wish to continue/start up activities when sensitive receptors are within the 250m boundary they should only be permitted to do so IF the processing and maturation activities are fully enclosed and even then they would require a bespoke permit.

The difficulty now arises if your operator wishes to set up an open windrow or partially enclosed facility at a distance of 250m to 500m away from sensitive receptors. It is clear that, under these conditions, problems will often arise. Our advice is that if your site requires a bespoke permit or falls into the 250-500m category then you must demand from your local EA office that nothing less than a full quantitative risk assessment for bioaerosols is prepared. If the EA do not seem inclined to ask for this (and our experience has been that the EA often do not challenge poorly written and non-sensitive qualitative reports), you must get the help of a specialist technical consultant to challenge this decision. Only such a document will show the likely exposure levels for nearby receptors.

What is a Quantitative risk assessment?

A quantitative risk assessment is a detailed modelling exercise carried out, taking account activity of the site, local climatic conditions throughout the day, and the local topography to provide a risk profile of how many times (over a 1 year to 5 year period) the safe levels of bioaerosols are likely to be exceeded. (For more details see ‘Bioaerosols submission‘ to Planning Inspector for Appeal at Old Sodbury site.)

In practice up until now (February 2009) the EA argued that, for open windrow sites, quantitative assessments could not be done. because of the inadequacy of the available ‘source data’ (explained above). Since the publication of the more accurate source data by Cranfield University, in December 2008, this is no longer the case. However, arguments about the optimum modelling techniques are still unresolved.

Unfortunately, a quantitative risk assessment for bioaerosols can cost upwards of £10,000 and is outside the reach of many resident’s groups. Unfortunately there are some rather unscrupulous environmental consultants out there who will provide what an operator wants. However, at this stage it is possible to pay one of the quality firms to critique the assessment and this would cost you rather less.

Beware of claims made in planning applications

If forced, the applicant will usually simply provide a qualitiative assessment on bioaerosols stating that the wind direction (which is taken from the nearest favourable wind rose data) proves that eg ‘sensitive receptors will only suffer from problems 10% of the time.’ This would still give residents a problem 36 days a year and is simply NOT sufficient. By its very nature wind direction is not site specific and does not take into account local climatic and topological conditions. If bioaerosol risk assessments were as simple as looking at wind diection, the whole science of dispersion modelling and fluid dynamics would not have been developed!

Background levels of bioaerosols must be provided. Since the effect of bioaerosols is CUMULATIVE, and background levels of bioaerosols in rural areas can often exceed the 1,000 cfum3, anyway such information is very important. Background levels increase during Spring -Autumn and are at their highest at the beginning and end of a day so provision of readings in the winter months at mid-day when wind dispersion is at its highest is simply a con.

Likewise carrying out bioaerosol measurements when the compost operation is not active is not worth the paper it’s written on. In the EA’s Technical Guidance on Composting Operations, October 2001 it is recognised that ‘bacteria and fungi are released into the air throughout the composting process but are particularly prevalent during operations such as screening, shredding and turning.’ They are particularly high during turning and it would not be unusual to record figures of >100,000 cfus within 10 metres of the site. Bioaerosols however, can also be released during spreading if the composting process has been cut short or not carried out properly and then there is real trouble because they are released from such a massive surface area.

When considering the impact of bioaerosols and their monitoring, it is important to realise that bioaerosols generally cannot be detected by human eye and they DO NOT smell so the Public are not aware when they are breathing them in.

The evidence of health problems: The theory

A chronology of the EAs changing position on bioaerosols and a summary of some of the key findings from the EA’s latest commisioned report on the risks (DEFRA WR0606) can be found here.

In the case of Old Sodbury the applicant submitted a desk–top bioaersol assessment. Our expert’s comments on the quality of this assessment are telling (see Critique of bioaerosol Report).This critique includes a full list of the health problems associated with emissions form compost sites (pages 6 & 7).

Certain people in the population are going to be particularly susceptible to the bioaerosols, the elderly(because of the high prevalence of pre-existing respiratory problems in this group), the very young (particularly under 6 year olds), any person with an existing chest complaint such as asthmatics, immunosuppressed individuals such as cancer patients and those suffering from conditions such as diabetes.

The most pernicious fungi generated by compost facilities is a fungi called Aspergillus Fumigatus. A recent case highlights how quickly death can be (Death by compost) for those who are genetically susceptible.

However, Aspergillus often lays dormant in people for many years and may only come to the fore if you suffer some damage to your immune system. Once it takes hold however, there is no ‘cure’ so these compost farms could well be a time-bomb in a similar way to asbestos.
To read more about the diseases caused in humans by Aspergillus, please refer to the following web-sites:

The evidence of health problems: The Practice

Michael Clapham MP, champion of rights for coal miners afflicted by lung disease, cites the situation at a green waste composting facility in Stourbridge. A consultant acting for the group has provided details of 12 residents whose health has been grossly affected by the site, 2 of the 12 developing Aspergilliosis (See and then page down to debate on ‘Open Windrow Composting’)

The technical adviser to the group has described the position in his own words to another local authority considering a similar application

In a case in Wakefield another man attributes his Aspergilliosis (and subsequent lung removal) to the nearby green waste transfer station (see Barnsley Chronicle)

We have recently (February 2009) been advised of case of Bronchiectasis -an allergic response to inhaled fungal spores caused by a compost farm in Stafford.

The endotoxins generated can produce meningitis in infants, and we now know of one operator who developed meningitis.

Obviously Aspergilliosis, bronchiectasis and meningitis are at the extreme end of the health problems that can be caused. However, many residents afflicted by compost sites report a worsening of conditions such as asthma, in itself an extremely upsetting and unpleasant condition. In Old Sodbury, although no official records were kept, the headmaster of the nearby primary school and the local cubmaster noted a significant increase in the number of inhalers required by the children.

Clearly all these cases have and are being raised with the EA. We ask just how many cases of a serious (possibly fatal) disease do these sites have to generate before action is taken?

Animal health issues

It has become clear that there are serious risks to livestock grazing close to compost farms (see veterinary report). When a farmer in Cheshire took the EA to court because the Aspergillus from an exempt open windrow compost farm were making their dairy herd miscarry, the EA did not amend their national policy accordingly but simply removed their responsibility for animal health (see Solicitor’s letter)! Animals not only inhale the airborne spores but also inhale and ingest the spores on the grass as they feed. As far as we have been able to establish no research has been carried out on the effects of compost facilities on grazing animals, even though the effects of Aspergillus on animals are well recorded in standard veterinary textbooks. No safe limits for animals have been established, so even if you do monitor, you could not establish that the levels are dangerous.

The Quality Meat Scotland Mark cannot be placed on any meat where the livestock have grazed on land where this green waste compost has been spread (Summary Decision).

The big supermarkets are not convinced of the disease-free nature of the compost generated by farms and are asking for more evidence before they will allow animals grazed on such land to be a source of meat for their shelves.

In conclusion therefore, the pressure to compost material is so great that the risks are being ignored and in our view it will take a number of court cases to force this policy to change.