A catalytic “cat” converter is a cylindrical device that attaches to an internal combustion engine as an addition to the exhaust system. Invented in 1950 in California in response to early studies being done on smog in Los Angeles, its purpose is to convert toxic exhaust into non-toxic substances. These can be attached to any internal combustion engines, but are most commonly found in automobiles. In 1973, the first catalytic converters hit the market, and soon after they were made mandatory by the government. The catalytic converter contains precious metals that are used to create reactions in the exhaust of engines to reduce the amount of environmentally harmful chemicals created from the burning of fuel in the engine.