Almost anyone can be cremated eventually, but several situations can delay or temporarily prevent cremation. These range from legal holds by a coroner to medical devices that pose explosion risks to the crematorium itself. In a few cases, the body may need special handling or a waiting period before cremation can safely proceed.
Bodies Under Coroner or Medical Examiner Jurisdiction
The most common reason cremation is blocked outright is a legal hold. When someone dies suddenly, under suspicious circumstances, or from violence of any kind, the county coroner or medical examiner takes jurisdiction over the body. This includes deaths in jail, unattended deaths, drug-related deaths, drownings, burns, gunshot wounds, and cases where death occurs within one year of an accident. In Washington State, for example, it is a misdemeanor to make final disposition of a body without the coroner’s consent when that body falls under their authority.
The reason is straightforward: cremation destroys evidence. If a homicide investigation develops weeks or months after death, investigators may need to re-examine the body. A coroner can hold a body indefinitely while an autopsy, toxicology analysis, or criminal investigation is completed. They can also retain organs, tissue samples, and stomach contents as evidence for court. Until the coroner or medical examiner releases the body, no cremation permit will be issued.
People With Pacemakers or Implantable Defibrillators
Cremation cannot proceed until pacemakers and implantable cardiac defibrillators (ICDs) are removed from the body. These devices explode at cremation temperatures, and the results can be dramatic. The first reported pacemaker explosion during cremation, in 1976, produced four rapid blasts followed by a fifth, punching a finger-sized hole half an inch deep into the cremator wall and leaving behind metal fragments resembling the ends of rifle cartridges.
Modern pacemakers use a lithium-iodine battery. At room temperature, they’re inert. But when a cremation chamber reaches 1,300°C (about 2,400°F), the iodine converts to gas and rapidly expands, bursting the casing. Simultaneously, the lithium melts and reacts with the iodine gas, releasing in under one second the energy the battery would normally expend over several years. In a survey of crematoria that had experienced pacemaker explosions, 45% reported damage to cremator doors, 42% reported damaged brickwork, and 3% had a cremator destroyed beyond repair. One facility reported staff injury.
Implantable defibrillators are even more dangerous, yet a survey found only 5% of crematoria staff were aware of their explosive potential. One crematorium reported a “large explosion” from an undetected ICD. Statutory cremation forms now ask whether the deceased has a pacemaker and whether it has been removed, but newer devices are getting smaller and harder to detect post-mortem while packing more energy.
Patients With Radioactive Implants
People who received radioactive seed implants for prostate cancer (a common form of brachytherapy using iodine-125) face a waiting period rather than an outright ban. The seeds remain in the body permanently and stay radioactive for months. Iodine-125 has a half-life of about 60 days, meaning it takes roughly 20 months (10 half-lives) for the radioactivity to drop to negligible levels.
If someone dies within that 20-month window, cremation is still possible but requires precautions. The crematorium worker should wear a mask and rubber gloves when handling the remains. The cremated remains should not be processed (ground down) as this could spread contamination. They should be placed in a metal urn rather than scattered. Scattering should wait until 20 months after the implant date. A radiation physicist from the treating clinic may visit the crematorium afterward to perform a radiation survey. Some Canadian provincial guidelines recommend a two-year waiting period as a simpler rule of thumb.
When Next of Kin Disagree
Cremation requires signed authorization from the legal next of kin, and if they can’t agree, the process stalls. The hierarchy runs from spouse to parents to adult children to siblings, then to more distant relatives in descending order. The critical rule: if multiple people share the same position in that hierarchy, all of them must agree and sign the cremation authorization form. Three adult children of a deceased parent, for instance, all need to sign. If one sibling objects, the cremation cannot move forward until the dispute is resolved, sometimes requiring a court order.
Beyond family consent, a cremation permit must also be issued by the county where cremation will take place, which requires a filed death certificate and the completed authorization form. Missing paperwork at any step delays the process.
Bodies That Are Too Large for the Equipment
Standard cremation chambers, called retorts, have physical size and weight limits. While these vary by facility, extremely large bodies present both logistical and safety challenges. Air quality regulators classify the cremation of obese individuals as an “unusual condition” that can produce higher levels of particulate matter, hydrocarbons, and other emissions. Some crematoria may decline cases that exceed their equipment capacity, though specialized facilities with larger retorts do exist.
Mercury Fillings and Environmental Concerns
Dental amalgam fillings are roughly 50% mercury by weight. Cremation temperatures far exceed mercury’s boiling point, so nearly all the mercury in a person’s teeth vaporizes and releases into the atmosphere. This is largely unregulated in North America. Canada and the United States have no specific rules limiting cremation based on dental fillings, and mercury emissions from crematoria are not subject to licensing frameworks in most jurisdictions.
The United Kingdom has taken a more aggressive stance, establishing an organization called CAMEO (Crematoria Abatement of Mercury Emissions Organisation) with a national goal of installing mercury filtration at a minimum of 50% of its crematoriums. The international Minamata Convention on Mercury, ratified by 69 countries including Canada, aims to reduce mercury releases broadly, but this has not yet translated into cremation-specific restrictions in most places. As it stands, mercury fillings do not prevent cremation anywhere in North America, though they remain an environmental concern that some countries are beginning to address.
Infectious Disease Cases
For highly dangerous infections like viral hemorrhagic fevers (including Ebola), the CDC actually recommends cremation as the preferred method of handling remains. Cremated remains are no longer infectious and can be returned to the family through normal procedures. Burial in a sealed metal casket is the backup option only when cremation cannot be safely performed, such as when the body contains an implanted device that might damage the chamber.
This is worth noting because it runs counter to what many people assume. There is no major infectious disease in the United States where cremation is prohibited by public health authorities. If anything, cremation is the preferred route for the most dangerous pathogens because it eliminates the infection risk entirely.
Religious Restrictions
No government in the Western world legally prohibits cremation based on religion, but several major faiths forbid or strongly discourage the practice for their adherents. Orthodox Judaism prohibits cremation, viewing the body as belonging to God and requiring respectful burial in the earth. Islam similarly requires burial, traditionally within 24 hours of death, and considers cremation a desecration. Eastern Orthodox Christianity has historically opposed cremation, though enforcement varies by community. The Catholic Church lifted its ban on cremation in 1963 but still expresses a preference for burial and requires that cremated remains be kept in a sacred place rather than scattered or divided.
These religious prohibitions carry no legal weight, but they matter practically. A family member who authorizes cremation against the known religious wishes of the deceased may face intense community or legal pressure from other relatives. In cases where the deceased left no written instructions, religious affiliation can become central to family disputes over disposition.