The claim to be “EPA Registered” has a certain amount of significance but also limitations as to what can be claimed by a product. Any product which is going to be sold as an additive to gasoline or diesel fuel must be registered with the EPA (Environmental Protection Agency). This is required and there are no exceptions to this. In order to receive permission from the EPA to sell the additives as an addition to fuel, the ingredients must be disclosed, with the specific purpose of ensuring that all ingredients in the additive are "chemically similar" to the fuel they are being added to. Hence, any gasoline additive cannot contain ingredients which are substantially different by nature to what is already in fuel. The purpose of this requirement is to prevent a company from trying to add unusual ingredients such as metals (aluminum. silica) or other compounds which are so different from the fuel that they would cause substantial damage to the engine or to the environment. That is what this “EPA Registered” claim mens-it simply means the company has fulfilled the legal requirements for letting the EPA know what is in their proposed product.