Finally, if you're planning your own funeral or memorial service in advance, you should inform your family about your end-of-life wishes to make sure they know what you want. Ideally, you should provide a written record rather than relying upon a family member's memory or keeping your plans on your computer, but even a single verbal conversation with your spouse or partner, child, sibling, or parent can prove better than nothing.
The Holocaust furnaces were supplied by a number of manufacturers, with the best known and most common being Topf and Sons as well as Kori Company of Berlin,[36] whose ovens were elongated to accommodate two bodies, slid inside from the back side. The ashes were taken out from the front side.[37] The furnaces were also unique, in that they were of a "stand alone" type, meaning that there was no visible duct work for the exhaust gases. These furnaces, based around a design commonly used for hospital incinerators, instead vented the gasses down through a series of ducts embedded in the floor, with the help of a draft fan located at the far end of the structure. Once outside, the gasses then rose through a free standing chimney, most notable for the fact that it was not directly attached to the structure of the building itself, nor had a visible duct leading into it.
Each cremation requires about 110 L (28 US gal) of fuel and releases about 240 kg (540 lb) of carbon dioxide into the atmosphere. Thus, the roughly 1 million bodies that are cremated annually in the United States produce about 240,000 t (270,000 short tons) of carbon dioxide, which is more CO2 pollution than 22,000 average American homes generate in a year.[74] The environmental impact may be reduced by using cremators for longer periods, and relaxing the requirement for a cremation to take place on the same day that the coffin is received, which reduces the use of fossil fuel and hence carbon emissions. Cremation is therefore becoming more friendly toward the environment.[75] Some funeral and crematorium owners offer a carbon neutral funeral service incorporating efficient-burning coffins made from lightweight recycled composite board.[76]
The idea that cremation might interfere with God's ability to resurrect the body was refuted as early as the 2nd-century Octavius of Minucius Felix, in which he said: "Every body, whether it is dried up into dust, or is dissolved into moisture, or is compressed into ashes, or is attenuated into smoke, is withdrawn from us, but it is reserved for God in the custody of the elements. Nor, as you believe, do we fear any loss from sepulture, but we adopt the ancient and better custom of burying in the earth."[85] And while there was a clear preference for burial, there was no general Church law forbidding cremation until 1866. Even in Medieval Europe, cremation was practiced in situations where there were multitudes of corpses simultaneously present, such as after a battle, after a pestilence or famine, and where there was an imminent fear of diseases spreading from the corpses, since individual burials with digging graves would take too long and body decomposition would begin before all the corpses had been interred. 
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