American Samoa's Congressman, Faleomavaega Eni Hunkin, claims that Exxon Mobil has admitted to off-loading substandard petrol supplies in the territory.
He says the petrol has been arriving for the last two years or more without the US government- required detergent additives.
The federal Clean Air Act requires fuel to contain the additive to reduce the formation of deposits in engines.
To knowingly sell or distribute petrol without the additive is a violation of federal law.
Faleomavaega says American Samoa should receive compensation from any fines to be imposed on Mobil.