Section 6 - Technical Aspects of Cremation
The Process of Cremation
6.1 Cremation is carried out in a purpose‑built furnace known as a "cremator". There are 10 different makes/models of cremator in use in Scotland. Although there is no correlation between the design and structure of a crematorium and the type of cremator used, the size of the population served by any crematorium is reflected in the number of cremators installed there. In all there are 34 cremators in use, 32 gas‑powered and 2 electric‑powered (see Annex O).
6.2 Cremators are generally controlled/operated by the software installed, which in all 32 gas-powered cremators currently in use includes an "infant" setting. A small number of small‑scale cremators, specifically designed for the cremation of non‑viable babies and possibly stillborn babies and the smallest of neonatal infants, have been installed in the past in England, of which only two are now in use. In Scotland there are none apart from the very recent installation at Mortonhall Crematorium, as noted by Dame Elish in her Report.
6.3 The modern cremators in use in Scotland are designed, built and operated to cremate bodies of many ages and sizes, but principally weighing between 60kg and 300kg (including the coffin). The cremator has 2 chambers, the main or primary chamber where the coffin is placed and cremated, and the secondary chamber or combustion zone where noxious gases and other pollutants are eliminated so far as possible prior to the discharge of exhaust through the flue. Additional pollution prevention equipment, referred to as "abatement plant", had to be installed by December 2012 "such that at least 50% of UK cremations are carried out in plants fitted with an abatement" (see Annex H). The purpose of abatement plant is to deal with pollutants which cannot be adequately eliminated by combustion, principally mercury.
6.4 In his expert report to the Mortonhall Investigation, combustion engineer Dr Clive Chamberlain, described the cremation process. The coffin is placed adjacent to the cremator on a bier, from which it is pushed ("charged" is the technical term) into the primary chamber either manually or by mechanical means fitted to the charger. The interior of the cremation chamber at the start of most cremations is in the range of 650oC to 850oC. Air for combustion is admitted to the chamber along its length in order to establish burning along the whole of the coffin and thereafter the ignition of the body. Body fat continues to fuel the process, at times raising the chamber temperature to around 1000oC. Full details of the cremation process are set out in Section 2 of the MIR  and in the report of Dr Clive Chamberlain (see Annex F).
6.5 When the flame has ceased and the cremation is complete and the remains have been removed from the chamber and allowed to cool, non‑combustible items such as coffin screws and handles, artificial joints and other metals, are generally extracted by the use of magnets or other means. The residue remaining comprises inorganic components of both the body, principally cremated bone, and the coffin and any other item in the coffin. These are ground down to a sand‑like consistency in a machine known as a "cremulator". The resulting contents of the cremulator are consigned to a container and referred to as the "ashes". In baby and infant cremations this may be done by hand.
6.6 In order that a cremation can be completed within a reasonable time, the combustion conditions within the primary cremation chamber are quite aggressive, comprising jets of air introduced along the cremator together with support burners to create the conditions necessary for active burning to take place. As a result, turbulence is created within the chamber. As Dr Chamberlain has explained in his report:
"This turbulence will entrain the lightest solid particles and carry them
out of the cremation chamber into the secondary combustion system."
The bones in an adult cremation retain enough shape and weight to remain in the primary chamber to be raked out but those of a baby may not. Any cremation residue that passes to the secondary chamber is lost and cannot be recovered. When a baby is cremated in the routine way that is applied in adult cremations, the risk that significant cremation residue will be lost in this way is ever-present.
6.7 As is plain from the MIR, until it became apparent at the end of 2012 that there were circumstances at Mortonhall Crematorium which required investigation, there was a fairly widespread understanding among those with a role to play in arranging or carrying out cremation, such as Funeral Directors and hospital gynaecology and maternity staff as well as some cremation technicians, that ashes were unlikely to be recovered when a baby was cremated, and that there might be no ashes recovered following the cremation of a stillborn baby or a very young infant.
Regulation of Crematoria and the Funeral and Cremation Industries
6.8 As in the case of any significant development involving the installation and use of potentially hazardous equipment, crematoria are subject to planning regulation, building control and health and safety requirements. Beyond that the only additional legislative controls that apply specifically to the practice of cremation are:
i) those relating to environmental protection, which are addressed below in this Section;
ii) those relating to the arrangements for a cremation to take place, including application, registration and the handling and disposal of the ashes, which are dealt with in Sections 9 and 10 of this Report;
iii) a requirement that every crematorium shall be maintained in good working order, provided with a sufficient number of attendants and kept constantly in a clean and orderly condition and
iv) a requirement that any crematorium shall be open to inspection at any time by "the person appointed for that purpose".
6.9 In keeping with this approach of light regulation of the practice of cremation and the associated professions, the power to inspect at (iv) above has seldom been used, the opening or closing of a crematorium is for the Cremation Authority to certify and intimate to Scottish Ministers, and not for the Scottish Ministers to decide to authorise, Funeral Directors are not regulated, and few statutory provisions apply to crematorium technicians. Whilst discussion on general regulation of the funeral and cremation industries arose in the course of the Commission's work, that is not a matter that could be addressed in the context of a review, like this, of a particular area of their work. However, specific regulation of baby and infant cremation is required, as is greater clarity in the rules which apply. Since this Report contains many recommendations for changes in rules and practice and it will take time to give effect to some, the Commission consider that a standing committee is necessary to oversee implementation and monitor change in order to improve and maintain standards. That committee will no doubt review developments and consider whether further regulation becomes necessary.
6.10 The applicable provisions relating to environmental protection are highly technical. Different provisions apply depending upon whether the cremation is in a full-scale cremator or a small-scale cremator designed for cremation of non-viable babies. Some that apply to full-scale cremators have a bearing on how baby cremations are conducted. In particular, they have a bearing on the question whether the practice followed in a number of crematoria, of cremating babies overnight, is compliant with those provisions or is in breach of one or more conditions of the crematorium operating permits. This is discussed further below and in Section 8. It is an important issue in light of evidence that following this course enhances the prospects of recovering ashes including remains of the baby.
6.11 A crematorium is a Part B installation in terms of paragraph (c) of Part B of section 1 of Schedule 1 of the Pollution Prevention and Control (Scotland) Regulations 2012 ("the 2012 Regulations"). The 2012 Regulations implement the requirements of the Industrial Emissions Directive (IED) as well as consolidating the Pollution Prevention and Control (Scotland) Regulations 2000 (the "2000 Regulations") as subsequently amended, which applied until January 2014. A permit to operate the crematorium is required. The competent authority responsible for granting permits is the Scottish Environment Protection Agency (SEPA) (see Regulations 10‑13). The activities authorised have generally been described as follows:
"The cremation of human remains and size reduction of cremated remains being activities falling within paragraph (c) of Part B of section 5.1 of Schedule 1 of the Regulations."
The type or types of cremator installed are identified and a condition applied requiring that they are so designed as to ensure that they can be charged only if the secondary chamber is above 800/850oC with a negative chamber pressure. The type of cremulator (for size reduction) installed is also specified.
6.12 There are standard conditions relating to administration, record‑keeping, reporting to SEPA, sampling and monitoring facilities, air emissions and the operation of the installation, all designed to minimise pollution of the atmosphere.
6.13 A strong emphasis is placed by the Regulations on the existence of appropriate and effective systems of management for installations to ensure a high level of protection of the environment. Explanatory notes attached to the permit include, as within the elements of a good environmental management system, that operating staff must be properly trained and that management must ensure that appropriate procedures are strictly adhered to.
6.14 In terms of Regulation 22 of the 2012 Regulations it is a condition of a permit for a Part B installation that the best available techniques for preventing or, where that is not practicable, reducing emissions from an installation must be used. Regulation 23 provides that SEPA must include in a permit for a Part B installation the conditions SEPA considers appropriate, when taken with Regulation 22, for the purpose of preventing, or where that is not practicable, reducing emissions into the atmosphere, taking particular account for that purpose of the general principles set out in Regulation 21(2). The general principles set out in Regulation 21(2) are that Part B installations should be operated in such a way that all the appropriate preventative measures are taken against pollution, in particular through application of the best available techniques, and that no significant pollution is caused.
6.15 At page 60 of the MIR a number of potential breaches of the Mortonhall permit conditions are identified as occurring when the cremation of a baby takes place overnight while the cremator is switched off and unattended. The conditions most likely to be breached are operating conditions relating to the maintenance of the combustion gases at 800/850 oC within the secondary combustion zone, the triggering of an alarm should the temperature drop below that figure, and the concentration of oxygen at the outlet from the combustion zone at not less than 6% by volume.
6.16 It is arguable, on the basis of the opinion of Dr Chamberlain, discussed at Section 9, that waiving the application of these conditions in the case of baby cremations and thus permitting overnight cremation would have no material adverse impact on the environment.
6.17 In the event that such amendment is considered to be a realistic possibility, an application would be dealt with in accordance with the following rules. Regulation 61 of the 2012 Regulations provides as follows:
"Scottish Ministers: Guidance to SEPA
61. (i) The Scottish Ministers may issue guidance to SEPA with respect to the carrying out any of its functions under these Regulations.
(ii) In carrying out any of its functions under these Regulations…SEPA must have regard to any guidance issued by the Scottish Ministers under this Regulation."
The currently applicable guidance is contained in Process Guidance Note 5/2(12) (PG Note) at Annex H.
6.18 In carrying out its responsibilities, SEPA, as a "Regulator", must have regard to the PG Note. The Regulations do not place any responsibility directly on Cremation Authorities to comply with the PG Note. However, paragraph 1.7 provides that the guidance is also for Operators "who are best advised also to have regard to it when making applications and in the subsequent operation of their installation." Paragraph 1.3 of the PG Note states that the purpose of the Note is to provide "guidance on the Best Available Techniques (BAT)". Permits issued by SEPA to Cremation Authorities to operate the crematorium are subject to conditions that are designed to ensure that "all the appropriate preventative measures are taken against pollution, in particular through application of the Best Available Techniques" - see Regulation 21(2)(a) and 22(1).
6.19 Another method of trying to maximise ashes recovery in baby cremation is to use a small-scale or "infant" cremator. They are dealt with in the PG Note at paragraph 5.28, which provides that small‑scale cremators may be developed in order to cremate stillbirth, neonatal and non-viable baby remains and that not all the standards for full‑scale cremators are then appropriate because of the relatively small mass of pollutants emitted. A small‑scale cremator is defined as a cremator with a maximum door opening of 300 × 300 mm and with a maximum length of primary chamber of 1000 mm. The few small‑scale cremators that have been built in the United Kingdom have conformed to these requirements. All of paragraphs 5.39 ‑ 5.53, relating to air quality and the management of emissions, apply to small‑scale cremators.
6.20 Both the ICCM and the FBCA regard the PG Note in paragraph 5.49 as requiring all crematorium technicians to be trained in their duties relating to control of the process and emissions to air. Whether it is an obligatory requirement is not clear. The PG Note also indicates that the ICCM and FBCA training schemes are adequate for that purpose. The ICCM and the FBCA regard completion of training as an essential pre-requisite of conducting a cremation unsupervised. The training schemes of both bodies not only deal with matters of environmental protection but also address other important subjects. Training is discussed in Section 11.