The body does not have to be embalmed for cremation unless the circumstances require it. Prior to cremation, any implants that use batteries (such as pacemakers) must be removed from the body. If left in the body, batteries may explode during cremation and cause damage to the cremation chamber or injury to the crematory operator. The body is usually placed in a container made of combustible materials (fiberboard, pressed wood, etc.) before it goes into the cremation chamber. (In some states a container is not required).