Sobibor extermination camp
In December 1941, SS officials at Chełmno did the first experiments to find ways of killing Jews using poison gases. At first, the Nazis used carbon monoxide gas to kill prisoners in vans. To get the carbon monoxide gas, they used a gasoline engine. They would connect the engine's exhaust pipe to pipes that led to the van's gas chamber. Carbon monoxide poisoning would kill all of the prisoners in the van.