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Public Radio's Environmental News Magazine (follow us on Google News)


Air Date: Week of

The Clean Air act requires reduced ozone and carbon monoxide in many urban areas. California, with nine of the ten most air polluted cities in the country, has some of the strictest air quality standards. To meet the standards, oil companies have reformulated gasoline using an additive called MTBE. MTBE has been used in gasoline throughout the nation for a number of years, but for the past year all gasoline sold in Cailfornia contains it. Now, MTBE, which the Environmental Protection Agency classifies as a possible carcinogen, is showing up in water, leading some critics to ask whether the state is sacrificing its water supply for cleaner air. Cheryl Colopy reports.


CURWOOD: The Clean Air Act requires reduced ozone and carbon monoxide in many urban areas. California, with 9 of the 10 most air polluted cities in the country, has some of the strictest air quality standards. To meet the standards, oil companies have reformulated gasoline using an additive called MTBE, and for the past year California has required it in all gasoline sold in the state. The Environmental Protection Agency classifies MTBE as a possible carcinogen, and it is showing up in water, leading some critics to ask whether the state is sacrificing its water supply for cleaner air. Cheryl Colopy reports.

(Motorized vehicles cutting through water)

COLOPY: Even on a weekday afternoon, motorboats and jet skis ply the waters of Colero Reservoir south of San Jose. The spring sky above the jet skiers is slightly smoggy, but it's cleaner than it used to be, partly because these engines, as well as all the cars in California, now burn gas that contains MTBE. The new additive allows the gas to burn more cleanly and efficiently than old style gasoline.

MAN: Man! That was great! Whoo-hoo!

COLOPY: But while the air may be cleaner, there's a new problem in the water. Traces of MTBE have been found in this and 2 other nearby reservoirs.

OBLONSKY: The more monitoring that's done daily, the more we're finding it. And I think that is alarming.

COLOPY: Engineer Sandy Oblonsky of the Santa Clara Valley Water District helps oversee the reservoirs. She says gas from motorboats is getting into these reservoirs and the District might have to ban recreational boating here if MTBE levels rise. But even that might not solve the problem. Ms. Oblonsky says a bigger source of MTBE pollution may be leaks from underground gasoline storage tanks. She says MTBE behaves differently from the other components of gasoline.

OBLONSKY: It's very mobile, and it will spread farther and faster than these other gas components. And that is a concern. As I said, though, we have not found it in any drinking water wells at this point. And that's why we are being very active now to get the fuel leak sites cleaned up, to look at leak protection.

COLOPY: But the very disaster Sandy Oblonsky and her colleagues are working to prevent in their district has already happened in southern California, where gas containing MTBE has been used for 2 years. The City of Santa Monica had to shut down half of its drinking water wells last year because of very high levels of MTBE: the result of leaking underground tanks, pipelines, or both. Santa Monica is now buying water and trying to get oil companies to pay for that and for cleaning up its water supply. Santa Monica's plight set off alarms in Sacramento. Now, the State Water Board requires all districts to test for MTBE.

(Fans and motors)

RODEGARI: Well, this is the instrument where the drinking water analyses for volatile organics are performed, and MTBE is a volatile organic. It's a class of organic compound that is considered volatile and easily purged out of water.

COLOPY: Here in the laboratories at the East Bay Municipal Utilities District in Oakland, water chemist Francois Rodegari supervises testing for 85 different organic compounds, including MTBE or methyl tertiary butyl ether.

BRAY: So what it does is it starts out at 35 degrees Centigrade, and then it ramps up to about 220, and that -- that heating acts as a means of separating the compounds you're looking for.

COLOPY: Chemist Tom Bray reads the results with the aid of sophisticated software, which determines what chemicals are in a water sample and at what levels. Francois Rodegari says so far there have been only tiny traces of MTBE in drinking water samples, again, from reservoirs that allow boating.

RODEGARI: It's a fairly new analysis and I think we don't fully understand all the ramifications of having added MTBE to gasoline. So we are still trying to understand what it means for our water supply.

COLOPY: The lab started testing for MTBE a couple of years ago when reformulated gas was first being used in California because the EPA had decided there was a chance very high levels might cause cancer in humans. EPA has since set a tolerance level of 70 parts per billion in water consumed over a lifetime. That's far more than what is showing up anywhere other than Santa Monica. But there's increasing unease about what the presence of lower levels of MTBE in water might mean, so California's water districts are struggling to define their own limits of tolerance for this new chemical. Meanwhile, a handful of scientists and environmentalists are saying get rid of it now.

(Voices in the background)

MARCHAND: If it's positive in the coloform then it turns yellow, and if it's possible for e-coli then it fluoresces.

COLOPY: John Marchand is a water chemist at another Bay Area water district, but it's in his capacity as an elected official for the Tri-Valley Water District east of Oakland that he's calling for a ban of MTBE.

MARCHAND: I don't support one huge experiment on the state of California while we determine whether MTBE was the best of all avenues to take.

COLOPY: As yet, no MTBE has shown up in his district's water, but Mr. Marchand hopes his district never ends up following in the footsteps of water districts like Los Angeles'.

MARCHAND: There are much larger agencies that are doing taste and odor profile analyses and talking about consumer acceptance levels. And that isn't where the discussion needs to be. It's not about mitigation. The discussion needs to be about preventing this from getting into our water sources in the first place.

COLOPY: At levels far below what the EPA sets as a health warning, MTBE can cause water to taste and smell like turpentine. So, chemist and wastewater treatment specialist Chuck Bennett agrees that California should get MTBE out of gasoline as soon as possible.

BENNETT: The health risks from MTBE really suggest that very high levels are tolerable amongst humans and animals. It's going to be an aesthetic acceptance or a nuisance situation. At levels of as low as 15 parts per billion, you're going to be able to smell the MTBE in your water. Or more accurately, when you take a shower in the morning, you're going to smell the MTBE coming out of your shower faucet.

COLOPY: Bennett's solution: switch to ethanol. Like MTBE, ethanol is an oxygenate, which helps gasoline burn more cleanly, but it won't pollute the water supply. The only problem with ethanol, he says, is that it's much less profitable for oil companies. MTBE is made from 2 inexpensive byproducts of gasoline production and is now a $10 billion a year industry. Ethanol is already the oxygenate of choice in the Midwest, while MTBE is used in smoggy parts of the Northeast and all of California. But the California Air Resources Board, which sets standards for air pollutants, cautions that one additive can't easily be substituted for another, and it emphasizes that MTBE has helped make the state's air better now than it's been for 40 years. Board representatives didn't want to talk about possible alternatives for MTBE, saying it's up to oil companies to decide which oxygenate to use. But as far as the oil industry is concerned, it's not an issue.

FOGARTY: There is no reason to ban MTBE in the state of California or anywhere else. According to the National Academy of Sciences, MTBE does not pose a significant human health risk.

COLOPY: David Fogarty, a spokesman for the Western States Petroleum Association, says ethanol is more expensive to make, and refineries in California have already invested $4 billion in retooling to make gas with MTBE.

FOGARTY: Without MTBE it could not, simply could not make cleaner burning gasoline. Switching to ethanol, for example, is probably not a viable option, because it increases evaporative emissions, increases summertime smog, number one. Number two is that there's a huge question of whether or not there'd be adequate ethanol supply to meet the needs of California.

COLOPY: For its part, the EPA doesn't see a problem with MTBE, either, when it's properly contained. Dick Wilson, the EPA's Deputy Assistant Administrator for Air and Radiation, says a problem arises only when motorboats and especially leaking underground gas tanks contaminate water supplies. And, he says, that can be prevented.

WILSON: It's absolutely possible, and obviously you need to do monitoring and you need to replace storage tanks that are leaking, because, you know, getting gasoline in drinking water is not a good thing.

COLOPY: Others aren't so sure it's an easy problem to solve. A recent US Geological Survey study indicates that traces of MTBE have begun to show up in drinking water all across the country. For Living on Earth, I'm Cheryl Colopy.



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