Guidance

Crematoria: best available techniques (BAT)

Published 4 December 2025

This document is part of the crematoria technical guidance. There are 4 more documents that cover this topic.

Read all the documents to make sure you have the information you need.

Environmental Management Systems (EMS) 

Pollutants targeted 

All pollutants. 

Principle of operation 

Effective management is central to environmental performance. It is an important component of BAT and of achieving compliance with permit conditions.  

All crematoria operators must ensure that the management of environmental performance is embedded within their management system whether by: 

• adopting published standards (such as International Standard (ISO) 14001) 001)
• setting up an environmental management system (EMS) tailored to the nature and size of the crematorium

As a minimum this will include: 

• commitment, leadership and accountability for the environmental performance of the facility 
• procedures and processes in place for achieving full compliance with all environmental permit conditions 
• setting objectives and targets for the continual improvement of environmental performance, measuring progress and revising the objectives and targets according to results  
• improving energy and resource efficiency 
• managing risks under normal operating conditions and in accidents and emergencies 
• proper management, supervision and training of staff 
• proper use of equipment 
• effective preventative maintenance of equipment 

Training 

Staff at all levels must have the necessary training and instruction in their duties relating to control of the process and emissions to air. As a minimum, this must include: 

• awareness of their responsibilities under the environmental permit 
• steps that are necessary to minimise emissions during start up and shutdown 
• actions to take when there are abnormal conditions, or accidents 

Appropriate training schemes include: 

• Crematorium Technicians Training Scheme operated by the Institute of Cemetery and Crematorium Management  
• Training and Examination Scheme for Crematorium Technicians which is run by the Federation of Burial and Cremation Authorities 

The operator must maintain a statement of the training requirements for each post and keep a record of the training received by each person. These documents must be made available to the regulator on request for inspection. 

Maintenance 

Effective preventative maintenance is a key part in achieving compliance with emission limits and other provisions. All aspects of the process including all plant, buildings and the equipment concerned with the control of emissions to air should be properly maintained.  

A well-maintained cremator will have written inspection, maintenance and cleaning programmes and schedules. This should include: 

• regular operator checks (daily, weekly or by number of cremations)  
• maintenance by the service engineer  
• periodic replacement of some items, such as brickwork  
• cleaning of cremator ducts and flues – as part of preventative maintenance 

The inspection and maintenance regime must include all parts of the equipment, instrumentation and control whose malfunction could have an impact on emissions to air.

Planned and preventative maintenance can be time based or condition based. All maintenance work should be recorded. Maintenance records must be made available to the regulator on request for inspection. 

Achievable performance 

Implementation of an EMS will support achieving a good level of environmental performance. 

Cross media effects 

An EMS provides a good framework for managing environmental impact across all media (such as air, water and land). 

Technical considerations relevant to applicability 

Regulators should use their discretion, in consultation with individual operators, in agreeing the appropriate level of environmental management.   

Economic information  

Effective management should ensure costs are controlled.   

Driving force for implementation 

Good management control over emissions. 

Good combustion control 

Pollutants targeted 

Volatile organic compounds, particulates (dust), carbon monoxide, odour, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo dioxins and furans (PCDD/F). 

Principle of operation 

To minimise and control emissions to air of carbon monoxide (CO) and unburnt substances from crematoria, this BAT is to ensure an optimised combustion. 

Optimised combustion is achieved by good design and operation of the equipment, including:  

• a primary combustion chamber into which the coffin and the deceased are cremated 
• a secondary combustion chamber which ensures the complete oxidation of all gaseous compounds passing from the primary combustion chamber 

The cremator should be designed in such a way that the gaseous products of combustion from the primary combustion chamber are held in the secondary combustion chamber at a sufficiently high temperature for a sufficiently long time to ensure they are completely oxidised. 

The cremator should be designed to achieve a minimum residence time in the secondary combustion chamber of 2 seconds at the operating temperature, and this is verified at commissioning. The secondary combustion chamber starts after the last injection of combustion air and ends where the temperature drops below the relevant minimum value set out in the operational controls in the guidance for crematoria: emissions limits, monitoring and other provisions. The temperature is measured at the start and end of the secondary combustion zone and both values must exceed the minimum value. 

Residence time in the secondary combustion chamber should be demonstrated at commissioning. This may require the temporary installation of additional thermocouples. The residence time requirement should be verified at the operating temperature of the secondary combustion chamber and that temperature must exceed the relevant minimum value set out in the operational controls in the guidance for crematoria: emissions limits, monitoring and other provisions. 

Unabated cremators should also be designed in such a way as to minimise the risk of entrainment of particulate matter by the gas flows. 

Achievable performance 

The main control is to ensure oxygen concentrations achieve the minimum conditions set out in Table 2 in the guidance document for crematoria: emissions limits, monitoring and other provisions. Carbon monoxide is a key indicator of incomplete combustion and should also be controlled below the level set out in Table 2. Controlling CO emissions will minimise emissions of unburnt organic compounds including PAH and PCDD/F, which are much more difficult to monitor.  

There is limited data available on PCDD/F emissions. For gas fired cremators fitted with flue gas treatment, emissions in the range 0.0004 to 0.014ng per Nm³ were reported (5 data points). For electric cremators, emissions in the range 0.006 to 0.018ng per Nm³ were reported. No data was reported for unabated cremators. 

Technical considerations relevant to applicability 

The cremator should be designed and operated in order to prevent the discharge of smoke or fumes during loading of a coffin into the primary combustion chamber. 

The charging system shall be interlocked to prevent the loading of a coffin into the primary combustion chamber unless the secondary combustion chamber temperature exceeds that specified for good combustion in the permit. 

The cremator and all ductwork should be made and maintained gas tight if under positive pressure to prevent the escape of gases from the ductwork or cremator to the air. 

When re-bricking a cremator, the convolutions of the secondary combustion chamber should be maintained. The volume of the chamber may need to be recalculated and residence time reverified. 

Economic information 

Cost effective operation of crematorium equipment. 

Driving force for implementation 

Good operational control of the cremation process. 

Example plants 

All cremators use this technique. 

Flue gas treatment 

Flue gas treatment is also known as mercury abatement or dry scrubbing process. 

Pollutants targeted 

Mercury, dioxins and furans, acid gases and particulate matter. 

Principle of operation 

Mercury is highly volatile and therefore almost exclusively passes into the flue-gas stream. Mercury is only partially removed with particulate matter. The rest remains in the flue gases as volatile compounds. 

This technique involves the injection of activated carbon into the flue gas upstream of a bag filter or another dedusting device. Mercury is adsorbed onto the reagent in the flue gas stream. If barrier filters such as bag filters are used, mercury is retained on the bag surface. 

Benefits include the reduction of mercury emissions to air by adsorption on activated carbon which also adsorbs dioxins. Bag filters also provide a means of dust and metals removal. It is normal for alkaline reagents to be added with the carbon which then allows the reduction of acid gases in the same process step as a multifunctional device. 

Alternatively, a fixed bed or cartridge of activated carbon and alkaline reagent can be installed downstream of a bag filter. 

Achievable performance 

Operational aspects are similar to other situations where bag filters are used. Effective bag filter and reagent injection system maintenance is particularly critical for achieving low emission levels.  

Where a fixed bed or cartridge is used, reagents must be replaced sufficiently frequently to prevent pollutant breakthrough. 

Mercury is adsorbed (usually at about 95% removal efficiency) to result in emissions to air below 30µg per Nm³. 

Cross media effects 

The cross-media effects are similar to those for other situations where bag filters are used. The energy consumption of bag filters is a significant aspect. In addition, for this technique the most significant cross-media effect is the production of residues contaminated with the removed pollutant (mercury).  

Cremators should be designed in such a way that the exhaust gases are rapidly cooled prior to flue gas treatment to prevent de novo synthesis (formation) of dioxins. 

Technical considerations relevant to applicability 

The applicability of bag filters is discussed in the section on particulate matter removal.  

Activated carbon injection is generally applicable to new and existing plants.  

The fire risk is significant with activated carbon. The adsorbent is normally mixed with either sodium bicarbonate or hydrated lime. 

The effectiveness of adsorbent materials may be reduced if used after expiry of the shelf life of the material. 

Economic information  

Mercury abatement is normally combined with the abatement of acid gas and particulate matter and so capital, installation and maintenance cost information generally relate to the whole system. 

Additional operating costs are from reagent consumption and disposal of residues as hazardous waste. 

Examples  

Mercury abatement is widely used throughout the UK. 

Efficient operation 

Pollutants targeted 

Carbon dioxide and nitrogen oxides. 

Principle of operation 

To optimise the consumption of energy operators should: 

• record the quantity of fuel and electricity consumed for each cremator or cremator and flue gas treatment equipment combination 
• carry out as many consecutive cremations as possible 
• operate equipment for the longest possible period between start up and shutdown 
• minimise periods of idling, meaning downtime between cremations when the equipment is kept hot, but is not operational 
• fit and maintain high standards of insulation materials to minimise heat losses 
• fit and maintain flue sealing dampers to minimise heat losses when the cremators are idle 
• fit heat recovery (read the technique on energy recovery) 

Achievable performance 

Industry data indicates that gas consumption drops from around 10m³ per cremation for 2 cremations to less than 5m³ per cremation for 6 or more consecutive cremations in the same operating period. 

Electric cremators operate differently in that they are maintained in a hot state even when non-operational. However, extended operation will also have energy efficiency benefits. 

Cross media effects 

Electricity consumption may reduce emissions of carbon dioxide at the crematoria, depending on the carbon intensity of the supply. 

Technical considerations relevant to applicability 

Applicable to all types of cremators. 

The ability to operate for long or extended periods with minimal down time may be limited locally by customer service needs and demand. 

All cremators with flue gas treatment will need to cool the exhaust gases for the treatment process to be effective. This is a heat recovery opportunity. At this scale of operation, heat will ordinarily be recovered as hot water. 

Economic information 

Efficient use of energy will reduce operating costs. 

Driving force for implementation 

Reasons for implementing efficient operation are to:  

• save money on the high cost of energy 
• reduce greenhouse gas and NOX emissions 
• reducing operating costs 

Example plants 

The most efficient use of energy will occur where equipment is operated 7 days a week, 24 hours per day, as may be the case in direct cremation. Direct cremation is where the cremation process takes place separately from the funeral service, for example either before or in the absence of a funeral service. 

For traditional crematoria, accepting short delays including overnight, between the funeral service and the cremation can facilitate improved scheduling to improve energy efficiency. 

Traditional crematoria may include some additional direct cremations within their schedule to improve energy efficiency. 

Energy recovery 

Pollutants targeted 

Carbon dioxide and other combustion related emissions. 

Principle of operation 

In crematoria with flue gas treatment, the energy recovered from cooling of the combustion gases prior to treatment is used instead of the energy that would otherwise have been needed for that purpose. 

Achievable performance 

Examples of where recovered heat could be used are: 

• to preheat of primary and secondary combustion air 
• space heating, for example hot water central heating of the chapel at the crematoria 
• other heating, for example greenhouses for horticulture 
• electricity generation using an Organic Rankine Cycle generator 

Cross media effects 

Improved overall energy efficiency. 

Technical considerations relevant to applicability 

Secondary air coolers are always likely to be needed which can take the full heat load from the cremator as matching the heat supply with demand will always be problematic. 

Economic information 

Reducing energy costs should have economic benefits. 

Driving force for implementation 

Energy saving. 

Examples  

The crematorium at Redditch uses recovered heat to heat the swimming pool in the local Leisure Centre.

The crematorium at Huntingdon uses recovered heat in adjacent greenhouses. 

Control of materials 

The control of materials includes the body bag, coffin construction materials and other materials placed in the cremator. 

Pollutants targeted 

Nitrogen oxides (NOX), hydrogen chloride (HCl), dioxins and furans, particulate matter, carbon dioxide and nitrous oxide. 

Principle of operation 

The operating principle is prevention at source.   

The range of materials used for coffin or casket construction includes cardboard, wickerwork (made from willow) as well as wood composite board and solid wood. Shrouds are also available and may use natural fibres such as cotton, linen or wool. 

Where possible, the weight of coffins should generally be optimised so that they provide sufficient strength and integrity to safely convey the deceased but minimise the quantity of additional ‘fuel’ for combustion. Resins (glue) with a high nitrogen content should be avoided. 

Materials to be avoided in coffin or casket construction, furnishings and body preparation and embalming include:  

• halogenates  
• metals (except steel screws and staples)  
• wax  
• more than a thin layer of water-based lacquer on wood 

Body bags 

Where a body bag is used, halogenated polymers and those with a high nitrogen content must not be used in the production of body bags. Double and triple bagging of the deceased should not be carried out. Packaging for stillbirth, neonatal and foetal remains should not include any halogenated plastics. 

Coffins 

Coffin handles, linings, clothing, and any personal effects placed in the coffin with the deceased must not contain polymers with a high halogen or nitrogen content (such as PVC or melamine). 

Cardboard coffins should not contain chlorine in the wet strength agent. For example, do not use polyamidoamine-epichlorhydrin based resin (PAA-E). 

Materials used in coffins must not produce ashes which may be sticky or cause fouling and slagging within the cremator. 

Coffins containing lead or zinc must not be cremated. 

Fuel 

Reducing the additional fuel load to the cremator reduces NOX formation in a number of ways. There is less: 

• material to combust, and the combustion is less intense which will reduce flame temperatures and so reduce the amount of thermal NOX produced 
• nitrogen embedded in the fuel which is also converted to NOX during the combustion process (for example, nitrogen present in the construction materials such as urea formaldehyde resins used in the production of some grades of MDF will be converted into NO or NO2 during combustion) 

Any chlorinated materials present will result in emissions of HCl during combustion. This will increase the emissions load on the flue gas treatment equipment. High levels of HCl increase the risk of dioxin formation during heat recovery. 

Achievable performance 

Reducing the thermal load and the avoidance of high nitrogen containing construction materials, or at least minimising the amount, will reduce the amount of NOX produced. 

NOX reductions of around 66% and N2O reductions of over 90% are claimed to be achievable by reducing the secondary fuel load at charging of the cremator. 

NOX reductions of around 66% are comparable with the performance of Selective Non-Catalytic Reduction (SNCR).  Read about this in the section on emerging techniques below.  

Cross media effects 

Chlorinated plastics and Nitrogen forming materials found in coffin materials should be minimised or avoided where possible due to formation of N20 (nitrous oxide which is 300 times more potent than CO2) and HCL in the combustion gases. Reduction or removal of such materials will lead to reduce consumption of abatement reagents and subsequent disposal costs once spent.

Technical considerations relevant to applicability 

The choice of coffin materials is normally made by the bereaved in consultation with the funeral director and is a matter outside the direct control of the crematoria operator.  

Operators should advise funeral directors so that they may give appropriate guidance to their customers. Operators are unlikely to refuse to carry out a cremation, except in extreme circumstances. 

Loading of coffins  

Whilst many models of loaders are suitable for use with lightweight materials, some loaders do not handle the softer, more flexible materials very well and may require modification. 

In some circumstances, there could be a risk of flash back when loading the coffin into the cremator if inappropriate materials are used with other intended consequences.

Economic information  

The cost of different coffin types and body bags is not a matter for this guidance.

Coffin choice should not impact on fuel consumption but could lead to a small increase in abatement reagent use. 

Driving force for implementation 

Reasons to implement control of materials include:  

• minimising emissions of NOX, particulates, acid gases, dioxins and furans 
• reducing the impact of crematoria on local ambient air quality 
• minimising greenhouse gas emissions 

Examples  

This BAT is applicable to all cremator types.

Lightweight coffins are readily sourced and are widely used in the UK.   

References  

1. Günther, Björn & Gebauer, Kathrin & Barkowski, Robert & Rosenthal, Michael & Bues, Claus-Thomas. (2012). Calorific value of selected wood species and wood products. European Journal of Wood and Wood Products. 70. 755-757. 10.1007/s00107-012-0613-z.  

2. Environmental Product Declaration - Medium Density Fireboard (MDF) (woodsolutions.com.au). 

3. Heat of combustion (wikipedia.org) 

4. P W Stephenson, P Cimbaly, D Simanovic, J Weber. Date of issue:  April 2008 Stack Emission Survey – Casket Combustion Trial LifeArt Australia Pty Ltd Eastern Suburbs Memorial Park Matraville, NSW Project no.: 3868/S11913A/07 

5. AP 42, Fifth Edition, Volume I Chapter 10: Wood Products Industry (epa.gov) 

6. Davies & Co.  

7. Nitrogen Oxides (NOX) Air Pollution Information System (apis.ac.uk) 

Emerging techniques 

An emerging technique is one which has the potential to provide either a higher level of environmental protection, or the same level of environmental protection in a more cost-effective manner, compared with existing best available techniques. 

Selective Non-Catalytic Reduction (SNCR) 

Pollutants targeted 

NOX – Nitrogen oxides, NO and NO2. 

Principle of operation 

Nitrogen oxides arise from combustion (thermal NOX) and from nitrogen that may form part of the materials being burned in the cremator. 

In the SNCR process, ammonia or urea is injected into the furnace to reduce NOX emissions. Ammonia reacts with nitrogen oxide to produce nitrogen and water. Where urea is used, the urea first reacts to produce ammonia and CO2 with the ammonia then reacting with nitrogen oxide. Nitrogen oxide is a precursor to nitrogen dioxide, so the technique is effective at reducing emissions of both NO and NO2. The reaction between ammonia and nitrogen oxide is most effective between 850˚C and 950˚C which is typically the temperature achieved in the secondary combustion chamber. 

SNCR is an established technique in other sectors but is included here as an emerging technique because its application to cremation is not yet optimised and not available from all equipment manufacturers. 

Achievable performance 

SNCR is used as a NOX abatement technique in combustion processes across a range of industrial sectors and can achieve reductions in emissions of between 60% and 80%. 

Limited data is available on NOX emissions because it is not a parameter that has to be monitored in permits. Available data shows NOX emissions typically from 200 to 350 mg/Nm³, with some values up to 500mg per Nm³. Only one data point for SNCR was obtained showing emissions of 114mg per Nm³. 

Cross media effects 

Overdosing of ammonia or urea results in ammonia slip, meaning emissions to air of ammonia. Poor control of the process can also lead to increased emissions of nitrous oxide (N2O) which is a potent greenhouse gas.  

On unabated cremators, SNCR can increase particulate emissions. 

Technical considerations  

Cremation is a batch process and thus emissions never achieve a steady state condition. To be fully effective, the injection rate needs to be controlled throughout the process to deliver the optimum dose at each part of the process. Crematoria are small pieces of equipment, and the installation of sophisticated control systems may not be economic. 

Economic information 

A simple system for dosing urea solution is relatively inexpensive. In February 2022 installation costs were reported as £20,000 to £25,000 per cremator. More sophisticated control systems would increase these costs.  

The ongoing supply of reagent will typically add £3 to £4 to the cost of each cremation. Additional maintenance costs are low. However, sophisticated control systems to optimise dosage across the cremation cycle could be expensive and are not used in practice. 

Driving force for implementation 

NOX emissions contribute significantly to poor air quality in urban areas. 

Examples  

One equipment manufacturer supplies a NOX abatement system for their gas-fired cremators using a fixed dosing rate of urea solution based on factory settings.

This document is part of the crematoria technical guidance.

Next: Crematoria: cremation standards in a national emergency