Facts on MTBE & THM

Facts on MtBE (Methyl Tertiary Butyl Ether)

  • Methyl tertiary butyl ether (MtBE) is added to gasoline to make it burn efficiently to help reduce air pollution from motor vehicles. It has also been added to gasoline since the 1970s to increase octane levels.
  • MtBE has been detected in water in a number of locations where it is used in gasoline. It is highly soluble and travels faster and farther in water than other gasoline compounds.
  • MtBE has a turpentine-like taste and odor, so even small amounts of MtBE make water unacceptable for drinking.
  • At elevated levels, MtBE may pose a public health threat.
  • Although some contamination is the result of car exhaust, leaking storage tanks are the leading source of water contamination from MtBE.
  • US EPA regulations currently require that underground gasoline storage tanks to be leak-proof and corrosion-proof.
  • The final deadline for all tanks was December 1998. 80% of regulated tanks meet current standards.
  • Surface waters are also contaminated from two-cycle engines, such as the kind used in personal watercraft that discharge up to 30 percent of their fuel unburned, leading to direct gasoline contamination of water resources.

Facts on THM (Trihalomethanes)

  • Chlorine is added to public water supplies for disinfection.
  • Chlorine disinfection has been extremely effective in limiting the outbreaks of such waterborne diseases as typhoid fever, dysentery and cholera.
  • Chlorine is a very active element. When added to a water supply reacts with other chemicals in the water. These reactions create new compounds as disinfection by-products or “DBPs.”
  • An example of DBP production occurs when organic acids from decaying vegetation find their way into water supplies. When these acids react with a chlorine agent, they produce new compounds, known as trihalomethanes or “THMs.”
  • THMs are linked to a number of serious health risks. Since then, regulations have been imposed for reducing THM levels to acceptable standards including the 100% removal of particular THMs.