MMT is used as a substitute for lead additive, which Ethyl also produced until recently. Many scientists believe MMT, which contains the heavy metal manganese, to be a potential public health hazard.
Automakers allege it gums up car engines.
Ethyl responded to the MMT ban with an unprecedented lawsuit. The company also argued that its reputation was damaged by the claim that MMT was harmful to human health. Proponents of the ban acknowledge that the scientific evidence around the health effects of MMT is uncertain, but say there is substantial cause for worry. They urge erring on the side of safety. In sum, the company argued, the government's action effectively expropriated its property, including its expected future profits and goodwill.