Cremation Process

The information that follows is intended to help the public more fully understand what occurs in the cremation process. The steps are detailed and should be carefully considered.

However, please note that this information has been prepared on a general basis. Because of variations in state/provincial and local laws, there may be some differences in legal requirements in different jurisdictions; your funeral service provider should be able to explain legal requirements in your area.

What is cremation?

Definition

Cremation is the mechanical, thermal, or other dissolution process that reduces human remains to bone fragments. Cremation also includes processing and pulverization of the bone fragments into pieces that are usually no more than one-eighth inch.

Types

This definition covers a variety of technologies that may be used in order to achieve reduction to bone fragments, including traditional flame-based cremation and alkaline hydrolysis.

Flame-based cremation uses flame and heat to reduce the human remains to bone fragments, or cremated remains. This is completed within a machine called a cremator. Flame-based cremation is the most common type of cremation, and is available through most funeral homes, crematories, or cemeteries. This process is detailed on this page below.

Alkaline hydrolysis reduces human remains to bone fragments, cremated remains or more specifically hydrolyzed remains, through a water-based dissolution process which uses alkaline chemicals, heat, agitation, and pressure to accelerate natural decomposition. Alkaline hydrolysis is a newer technology, and is currently only available in a few states and provinces in the U.S. and Canada. Where alkaline hydrolysis is accepted, there are limited providers available. For details on this process, visit our alkaline hydrolysis page.

Flame-based cremation and alkaline hydrolysis are the legal cremation processes in the US and Canada at this time. Additional processes may be in development but not currently accepted by the regulators.

An Overview of Cremation

There are at a minimum four main elements of cremation.

Transportation of the deceased from place of death to the crematory.
Secure, cold storage of deceased prior to cremation
The cremation process itself
Return of cremated remains to the authorized agent

When comparing prices and providers, ensure each element is included in the price and ask questions about the specific policies and procedures for chain of identification at each step.

You may still choose to have a visitation or viewing prior to cremation, which may involve embalming, setting features or washing and dressing the deceased. You may also arrange to witness the cremation itself.

Transportation

The deceased will be removed from the place of death and taken to a funeral home; on rare occasions they may be taken directly to the crematory. From the point of removal on, the deceased’s identity is carefully confirmed at each step in the process. This ensures that a chain of identification is firmly established.

Storage

It takes time to finalize the paperwork and make plans, so until the services are planned and the cremation is scheduled, the deceased will be placed in secure, cold storage. The time between death and cremation can vary considerably based on many factors; cremation typically occurs at least 48 hours after death.

Steps in the Cremation Process

The deceased will be placed in a cremation container. The minimum requirement for a cremation container is that it be completely enclosed, rigid, leak resistant, and combustible. You may select a cardboard or particle board container, rental casket, a wooden casket, or even a highly polished casket, provided it is combustible and non-toxic. Metal caskets cannot be cremated.
Facility staff will confirm the identity of the deceased by checking all paperwork. A cremation number or other identification (id) will be assigned. This number/id is often stamped onto a stainless steel disc, but may also be in the form of a barcode. The id/number is recorded on a cremation log. The stainless disc remains with the remains throughout their entire time at the cremation facility.
When it is time for the cremation of the deceased, they will be removed from the storage unit and their identification will be confirmed using paperwork and the stainless disc. The container will be taken to the cremator unit and placed on a table in front of the cremator door.
The door of the cremator will be opened, and the container will be placed inside the primary chamber. Usually this is performed manually with the aid of cardboard rollers or mechanically with a rolling conveyor loader. The stainless disc with number/id will be placed inside the cremator with the remains.
The door will be closed and the cremation monitored carefully until it is completed. The process can take anywhere from 30 minutes, as in the case of a stillborn, to over two hours depending on the body size and stored heat in the chamber.
When the cremation process is complete, the door will be opened and identification checked again against paperwork and the stainless disc. The bone fragments that remain, now called cremated remains, will be carefully swept out of the cremator into a cooling tray, allowed to cool and taken to a processor.
The processor is a machine that uses blades to pulverize the bone fragments until the remains are less than 1/8” in size.
The cremated remains are then transferred to a strong plastic bag and placed in either an urn or temporary container if the family has not selected an urn yet. Identification is checked again and the stainless disc is placed in the container with the remains. The urn and its box are labeled with identifying paperwork and checked again before being stored for the family’s retrieval.

The Technical Details

The process of cremation is essentially the conversion of a solid to a gas. This is accomplished by heating the body, which contains between 65% and 85% water by weight, to a temperature high enough to facilitate the combustion process. Laws for required temperatures vary by state, but the cremation process usually occurs between 1400 and 1600 degrees F.

The combustion process in the cremator proceeds in two stages — first is primary combustion of the deceased in the main chamber of the cremator. Tissue, organs, body fat, and casket or other container materials burn off as gases and move to a secondary chamber, where they continue to undergo combustion. The bone fragments remain in the primary chamber. The inorganic particles, usually from the cremation container, settle on the floor of the secondary chamber. The gases formed as a by-product of combustion such as carbon dioxide, water, oxygen, etc. finally discharge through a stack in the roof of the crematory building.

What can be cremated?

Personal items of the deceased, such as jewelry, watches or other items will be removed from the container and returned to the family with prior arrangement. Sometimes families request that items of significance be cremated with the deceased. In some cases this can be allowed, but in many cases it cannot. This is for safety reasons, as not everything is combustible and may cause damage to the equipment or the operator if left in the container. The funeral director will advise the family on what can or cannot be put in the container.

What is in the cremated remains?

The bone fragments that remain in the primary chamber are mostly calcium phosphates, with some other minor minerals. Cremated remains are generally white to gray in color. Additionally, there may be pieces of metal in the cremated remains – this metal may come from surgical implants like hip replacements, dental fillings, casket handles, or jewelry that was not removed prior to cremation. The metal is separated from the cremated remains before they are processed (pulverized). The metal is typically recycled

The average weight of adult cremated remains is between four and six pounds; a tiny percentage of the body’s original mass. The cremation chamber is either swept thoroughly or vacuumed with specially designed equipment to retrieve as much of the remains as possible.

How do I know I'm getting my loved one's remains back?

Chain of custody refers to the chronological documentation of the custody, control, transfer, analysis, and disposition of remains and personal property. This is an important definition. Cremation is an irreversible, unstoppable process. Every step of the process needs to be documented, from the receiving of the human remains to the ultimate disposition of the cremated remains, including returning the cremated remains to the authorized agent.

Identification checkpoints:

Removal of deceased from place of death
Transport to crematory
Placement in storage
Placement in cremator
Removal from cremator
Processing at pulverizer
Placement in urn
Return to authorized agent

It is important to note that each state/province requires different operational data to be recorded, and requires specific forms of documentation, thus each facility may have different policies and procedures which will vary slightly from the above. The funeral director can advise the family of what their facility’s procedures are and what to expect.

Glossary of Cremation Terms

Alkaline hydrolysis: the reduction of a dead human body to essential elements through a water-based dissolution process using alkaline chemicals, heat, agitation, and pressure to accelerate natural decomposition, the processing of the hydrolyzed remains after removal from the alkaline hydrolysis vessel, placement of the processed remains in a hydrolyzed remains container, and release of the hydrolyzed remains to an appropriate party. Learn more about alkaline hydrolysis and where the process is accepted here.
Authorizing Agent(s): the person(s) legally entitled to control the disposition of human remains.
Alternative container/Cremation container: the case in which the human body is delivered to the crematory and in which it is cremated.
Casket: A rigid container that is designed for the encasement of human remains, usually constructed of wood, metal, or like materials and ornamented and lined with fabric, which may or may not be combustible.
Cremation: the mechanical and/or thermal or other dissolution process that reduces human remains to bone fragments. Cremation includes processing and usually includes the pulverization of the bone fragments. This definition covers a variety of technologies that may be applied in order to achieve reduction to bone fragments, including traditional flame-based cremation and alkaline hydrolysis.
Direct cremation: a cremation that occurs without any formal viewing of the remains or any visitation or ceremony with the body present.
Cremated remains: All the remains of the cremated human body recovered after the completion of the cremation process, including pulverization which leaves only bone fragments reduced to consist of unidentifiable dimensions.
Cremation chamber: The enclosed space within which the cremation process takes place.
Cremation container/alternative container: the case in which the human body is delivered to the crematory and in which it is cremated.
Cremation interment container /urn vault: A rigid outer container that, subject to a cemetery’s rules and regulations, is composed of concrete, steel, fiberglass, plastic, or some similar material in which an urn is placed prior to being interred in the ground, and which is designed to withstand prolonged exposure to the elements and to support the earth above the urn.
Cremator: The total mechanical unit for the cremation process. Inside it is lined—top, sides, and bottom— with a heavy refractory tile or brick, with a layer of insulation between the inside surface and the outside protective housing or casing.
Crematory/Crematorium: The building that houses the cremation chamber(s). It can be a building that serves this one function or a multi-purpose building that also contains the administrative offices, mortuary preparation rooms, or cemetery maintenance facilities.
Crematory Operator: The individual who is authorized and licensed by the board to operate the cremator and perform the cremation process.
Disposition: The shipment, interment, burial, cremation, or anatomical donation of a dead human body or parts of a dead human body.
Embalming: disinfecting, preparing, or preserving for final disposition of dead human bodies.
Final disposition: The burial or other disposition on a permanent basis of a dead human body, cremated remains, or parts of a dead human body.
Funeral Director: A funeral service professional employed as a licensed “funeral director” or “funeral director and embalmer” as defined by state law to practice funeral directing or funeral directing and embalming.
General Price List (GPL): contains identifying information, itemized prices for the various goods and services sold, and other important disclosures.
Human remains: The body of a deceased person, or part of a body or limb that has been removed from a living person, including the body, part of body, or limb in any stage of decomposition.
Interment: The act or ceremony of burying a dead human body.
Inurnment: The act or ceremony of burying an urn containing cremated remains.
Pre-need arrangements: planning and/or prepaying for cremation/burial, services and goods in advance.
Provider, Funeral or Cremation: a business that sells or offers to sell both funeral goods and funeral services to the public.
Processing: the pre-pulverization process of removing any foreign materials (non-body and container) from the cremated remains in preparation for pulverization.
Pulverization: the reduction of identifiable bone fragments after the completion of the cremation and processing to granulated particles by manual or mechanical means.
Temporary container: A receptacle for cremated remains usually made of cardboard, plastic, or similar material designed to hold the cremated remains until an urn or other permanent container is acquired.
Urn: A receptacle designed to permanently encase the cremated remains.
Urn Vault/cremation inurnment container: A rigid outer container that, subject to a cemetery’s rules and regulations, is composed of concrete, steel, fiberglass, plastic, or some similar material in which an urn is placed prior to being interred in the ground, and which is designed to withstand prolonged exposure to the elements and to support the earth above the urn.