The process takes place in a cremation chamber, also known as a retort. The chamber is preheated to a specific point and has mechanized doors to avoid heat loss. While performing a cremation, temperatures in the chamber reach between 1400 to 1800 degrees Fahrenheit.
First, the body must be placed in a casket or container. These must be composed of a combustible material so they can easily burn down. The body and the container are then placed in the cremation chamber and burned by flames that are produced by a furnace fueled by natural gas, oils or propane.
So what exactly happens to the bodies as they burn? First, the heat dries out all the moisture. Then, the skin and hair begin to burn. The muscles are charred, the soft tissue is vaporized and the bones are calcified, so they become very brittle.
You may wonder if there's an awful smell during all of this. Luckily, crematoriums are equipped with powerful exhaust systems that discharge the gas. The bodies are mostly burned one at a time to keep the emissions low, and they are processed meticulously to avoid any powerful stenches.
From here, some crematoriums have a secondary afterburner. This helps completely disintegrate the remains. If they don't have this, a cremation technician may have to grind down the partially cremated remains with a long hoe-like rod.
At this point, the body has been reduced to bone fragments. It's then collected in a tray or pan and allowed time to cool. As much of it is ash at this point, some residue may remain in the chamber and mix in during future cremations.
These gathered remains aren't just bones and ash, however. Once they have cooled down, they must be sifted through to remove certain objects and items. For example, pieces of the burned down casket or container, including screws, nails and hinges.
The mixture may also contain dental work, such as dental gold, surgical screws, prosthesis or implants. These are removed with the help of powerful magnets or forceps after manual inspection. These items are then disposed of in accordance with local laws.
What about jewelry? Can a deceased loved one have a cherished ring, necklace or watch burned with them? It's not recommended, as they can break down during cremation and cause complications, especially during the next phase of the process.
Overall, the entire process of cremation takes on average between one to three hours. It transforms a human body into about three to seven pounds of cremains. The final product is pasty white in color.
The last step is the collection. The remains are transferred into an urn and given to a relative or representative of the deceased. If you don't have an urn, the crematorium will place them in a box or other container.