Gas chamber carbon monoxide as the lethal agent. Sometimes a box filled with anesthetic gas is used to anesthetize small animals for surgery or euthanasia. Gas chamber A gas chamber is an apparatus for killing humans or other animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced. The most commonly used poisonous agent is hydrogen cyanide; carbon dioxide and carbon monoxide have also been used. Gas chambers were used as a method of execution for condemned prisoners in the United States beginning in the 1920s and continue to be a legal execution method in
Electric bus and unpleasant exhaust fumes. However, improvements were made to the gasoline-powered car that caused the electric car to lose some momentum. The hand crank was soon replaced with an electric starter and gasoline-powered vehicles became more affordable. Gasoline cars soon overcame the popularity of electric powered vehicles. By 1935, electric cars practically disappeared. It was not until the 1970s when a gas shortage hit, causing gas prices to soar, that electric cars entered back into the marketplace. Gasoline-powered cars still remained more popular due to better performance and reliability. The 1990s saw electric cars made more popular as societal concern