Another side to fuel additive debate |

Another side to fuel additive debate

Brian Bose

Despite growing concerns over a controversial gasoline additive and support by many to have it banned, the air quality benefits resulting from its use may keep the issue blowing in the wind for some time.

“We think it’s a beneficial addition and the cleaner-burning gasoline overall has been successful,” said Alan Hirsch, spokesperson with the California Air Resources Board. “It has delivered the benefits we expected, reducing smog and cancer-causing toxins in the air.”

The controversial additive is methyl tertiary butyl ether, which is put in gasoline to help improve combustion and cut down on the amount of carbon monoxide released from cars and other gas-powered engines. MTBE is a byproduct of the oil refinery process, said Hirsch, and its high oxygen content makes it a good additive.

It was first introduced to American gasoline by oil refineries in 1979.

“The oil industry did it voluntarily, outside of any governmental regulation,” Hirsch said. “The U.S. Environmental Protection Agency certified its use in gas three times, in 1979, 1981 and 1988. Basically, the EPA OK’d it, and the state (of California) allows it.”

According to Hirsch, the use of MTBE increased in the 1980s. It wasn’t until 1990 that the federal government finally stepped in and passed a law that required gasoline in smoggy regions to be oxygenated with MTBE or ethanol. Since MTBE was readily available, and in large quantities, it became the compound of choice.

“It helps the gasoline burn more efficiently and reduces the amount of carbon monoxide, which is more of a threat in the Lake Tahoe area than most other parts of the state (because of the altitude),” Hirsch said. “It also helps reduce smog-forming emissions.”

Many people calling for an immediate ban on the additive also want to replace it with ethanol, an alcohol derived from agricultural crops such as corn. Hirsch said using it is definitely possible, but the federal regulations regarding vapor pressure will have to be changed in order to get the majority of oil refineries to switch to the new additive. Ethanol has a high vapor pressure, which leads to a quicker evaporation rate, and thus a higher release of other pollutants.

“The ethanol vapor molecules blend with other gasoline molecules and can get converted to ozone quicker (than MTBE), which is a major component of smog,” Hirsch said. “You would have to overcome the vapor pressure, so from the oil refineries’ standpoint it is easier to use MTBE.”

There is also the question of abundance. Currently, there is about one gallon of MTBE in every 10-plus gallons of gasoline. Hirsch said MTBE is the only oxygenate that can meet California’s enormous gasoline needs. Also, if MTBE is banned, the oil refineries will have to revamp their entire operations.

“It will be very challenging to blend with ethanol blends and still meet federal requirements,” said Aeron Arlin Genet, external affairs coordinator for Western States Petroleum Association, a nonprofit organization that represents the petroleum industry in the western United States. “If MTBE is banned today, we will have to reconstruct and retool the refineries.”

Arlin Genet said that while several of the oil companies are against the replacement of MTBE with another substance such as ethanol, the organization is still not against changing to another oxygenate. The main goal, she added, is simply to meet the air quality regulations that are set by the federal government.

Officials with CARB are supporting a bill that is in Congress that will make the federal regulations, namely vapor pressure, more flexible. While they await the federal decision, they are also discussing ways to loosen state regulations.

“We are doing several things to try to make regulations as flexible as possible. Hopefully we will create a process through which we will let the refinery choose what oxygenate to use, just as long as the alternative gasoline burns as cleanly as the clean-burning gasolines do today,” Hirsch said.

There is a company called Tosco that is currently conducting an ethanol pilot program in the Bay Area, Hirsch said. The company is selling gasoline with ethanol as the additive at a number of Union 76 stations in the greater San Francisco area.

A relatively new issue, there are a number of agencies throughout the country conducting tests regarding the overall health and environmental effects caused by MTBE. While many questions remain unanswered, the contaminant continues to find its way into a number of drinking water wells and surface water sources.

“We will continue to try to get the law changed because we feel that unless changes are made, it will be difficult for refineries to move away from MTBE,” Hirsch said. “While I believe ethanol is a beneficial additive, we shouldn’t push its use and it should be left up to each refinery.”

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