IF YOU were lucky enough to join the film stars and sporting heroes in Colorado for the skiing last winter, you’ll have noticed that the petrol in some parts of the state smells slightly sweet and fruity – and costs up to 10 cents per gallon more than conventional fuel. That’s because it contains ethers and alcohols, oxygen-rich compounds that are designed to prevent the build-up, especially in cold weather, of carbon monoxide from car exhausts.
Colorado led the way in 1988 when Denver became the first city to introduce the additives on the basis of research claiming that they helped the fuel’s hydrocarbons to burn more efficiently at low temperatures, thereby producing more carbon dioxide than CO and also reducing emissions of the polluting hydrocarbons themselves. Within four years, the use of oxyfuels during winter had become compulsory in 35 cities across the US, even though they lifted petrol prices by as much as 15 cents a gallon.
But a growing body of opinion now challenges these claims, and in the absence of definitive research – or indeed, much research at all – the jury is still out on oxyfuels. Although CO levels have dropped in all but two of the cities, some scientists say that oxyfuels are not responsible for the improvement. The introduction of catalytic converters is more likely to be responsible, they argue, and oxyfuels actually cause higher levels of other pollutants. Other researchers point to anecdotal evidence suggesting that oxyfuels are a greater health hazard than conventional fuel. One thing that unites most of them is that the full effects of oxyfuels were not understood when the American legislation was drawn up.
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And for Europe, the problem is only just beginning. In spite of the counterclaims, at least one chemical company has already started to lobby for the introduction of oxyfuels just as the European Commission, in association with the European oil and car industries, is about to publish a report on future fuels. The joint report, due to be published next week, will consider the effects of different formulations of petrol on exhaust emissions. This information is essential for European law makers who must set emission limits and fuel specifications by 2000.
There is little dispute over how oxygenated fuel works. Cars produce CO when there is too little oxygen in the fuel-air mixture to convert all the carbon in the petrol to CO2. The process is particularly inefficient at low temperatures, so emissions are at their highest after cold starts in winter. The Environmental Protection Agency estimates that in the first 3 to 5 minutes of starting up the engine, a car emits more than 60 per cent of the pollutants it produces in an average drive. For city drivers on short trips, during which the engine has no time to warm up, this figure could be even higher.
Oxygenated fuel tackles this problem by providing its own oxygen to help the petrol burn. This is added in the form of chemicals such as methyl tertiary-butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), methanol or ethanol.
The US government stoutly defends its actions. “It is disingenuous to say that oxyfuels have brought no benefits,” says David Kortum, head of technical analysis at the EPA Office of Mobile Sources in Washington DC. According to the EPA, concentrations of CO fell by between 10 and 15 per cent in most of the cities using oxyfuels.
Art Zadrozny, spokesman for the Oxygenated Fuels Association, which represents American producers of the fuels, agrees with the EPA. “There is very strong evidence that oxyfuels are doing something.” Zadrozny points out that catalytic converters do not reduce emissions until they have warmed up. In winter, and in old cars, oxygenates come into their own, he insists.
Green light
Environmental groups are also in favour. “Oxyfuels have resulted in substantial air quality and public health improvements. They have practically wiped out CO emissions,” says Deborah Shprentz of the Natural Resources Defense Council, an environmental lobbyist based in Washington. “On balance, they seem to provide a net benefit.” The Colorado state government appears to have few doubts about the value of the additives. From computer models, its Department of Public Health and Environment estimates that oxygenated fuels cut emissions of CO by 25 per cent.
But there are plenty of dissenters. Larry Anderson, a chemist at the University of Colorado in Denver, has measured the concentration of CO in the city’s atmosphere since 1981. Anderson has found a clear drop in emissions even in summer when oxyfuels are not used. The real reason for the drop is cleaner cars, he says. Since 1985, all new cars in the US have been fitted with catalytic converters that oxidise hydrocarbons and CO to CO2, and reduce nitric oxides to nitrogen. The cars also have an oxygen sensor in the exhaust system to control the fuel-air mix in the engine. “Oxyfuels were the solution to a problem the US had ten years ago. Now they are completely unnecessary,” he says.
Another sceptic is John Heywood at the Department of Mechanical Engineering at the Massachusetts Institute of Technology. He says that when oxyfuels became compulsory, there was little information about the way that fuel additives affect emissions. Heywood believes that the introduction of oxygenated fuel was partly a result of a political compromise between industry, Congress and the EPA. “Nobody has been able to show that they bring down CO levels in the field,” he says, arguing that there is no clear evidence that they cut hydrocarbon emissions either.
More disturbingly, some researchers have found evidence that oxyfuels can produce pollution of their own. If ethers and alcohols burn incompletely, they form aldehydes. MTBE and methanol produce formaldehyde, while ETBE and ethanol produce acetaldehyde. The EPA says that both by-products may well cause cancer in humans. Acetaldehyde is also the precursor to peroxyacetyl nitrate (PAN), a compound that is toxic to plants and can induce genetic mutations.
Anderson has studied levels of both formaldehyde and acetaldehyde in Denver since 1987. He says that the concentration of formaldehyde increased significantly after 1988 and peaked in the winter of 1991/92, when he measured one of the highest levels of formaldehyde ever recorded in a city. Since then, he says, some fuel companies have started to replace MTBE with ethanol, and levels of formaldehyde have eased off. Anderson credits cleaner cars with keeping acetaldehyde concentrations constant since 1987.
The EPA recognises the problem with formaldehyde but says that reducing levels of CO is worth the risk. “Vehicles emit a tiny amount of formaldehyde compared with building materials,” says Kortum. For example, the glue that holds plywood together and many types of plastic produce formaldehyde when they are oxidised. “In comparison, vehicles do not present a significant problem,” he adds. According to Zadrozny, the increase in formaldehyde emissions is more than balanced by the decrease in benzene emissions. “Benzene is a much more toxic cancer hazard,” he points out.
In addition to the question mark hanging over the pollution generated by oxyfuels, there is also the problem of health hazards. Bob Wages, president of the Oil, Chemical and Atomic Workers International Union based in Denver, is concerned that the long-term health effects of additives such as MTBE are poorly understood, and is battling for more research. He believes that petrol companies have used workers in the oil industry as guinea pigs. Wages reports anecdotal evidence of acute illnesses, such as nausea and asthma, among oil workers involved in the production of oxyfuels. “Let’s face it, we’re talking about the same people that said there was no problem with benzene, asbestos, and a host of other chemicals,” asserts Wages. “There’s no problem until people start dying.”
Cancer evidence
There is no doubt that MTBE causes cancer in animals according to Myron Mehlman, an occupational health scientist at the University of Medicine and Dentistry of New Jersey. In the late 1980s, researchers at Union Carbide’s Bushy Run Center near Pittsburgh discovered that very high doses of MTBE caused liver cancer in female mice and kidney cancer in male rats.
Mehlman says it is also likely to cause cancer in humans, and other illnesses as well. He claims to have seen up to 800 patients with symptoms that developed immediately after oxyfuels were introduced in New Jersey. They complained of headaches, insomnia, nausea, rashes and breathing problems after filling their cars with oxygenated fuel, or going for a drive using it. And he says he knows of similar cases in seven other states. “Based on all available information, consumers should not be exposed [to MTBE]. We have to find an alternative, too many people are getting sick.” Mehlman predicts more cancers, especially in children and pregnant women.
This week, a pressure group in New Jersey is due to present the state governor with a petition backed by 16 000 signatures seeking a ban on MTBE in petrol. The only benefit MTBE brings is in the form of profit for the producers, says Mehlman. Oxyfuels that lift the price of petrol by 15 cents per gallon are worth about $12 billion per year to the oil industry, he adds.
Last winter, 700 citizens of Milwaukee, Wisconsin, reported a rash of illnesses – dizziness, nausea, headaches, coughs and skin problems – that they blamed on a new type of reformulated fuel, which contained additives that included a high concentration of oxygenated compounds. Public concern forced the state governor to ask the EPA to suspend the laws that made oxyfuels compulsory. The agency refused. A study by the Wisconsin Department of Health found no evidence linking exposure to the petrol with ill health.
Brian Leaderer, head of environmental health sciences at Yale University’s school of medicine, also failed to link MTBE with ill health. Two years ago, he carried out tests exposing volunteers for up to an hour to MTBE and a mixture of MTBE and 17 different hydrocarbons resembling petrol. But Leaderer could find no signs of impaired mental agility, memory or mood, eye irritation or redness, or nasal inflammation in the volunteers.
But Leaderer points out that his research was conducted at standard temperature and humidity. Complaints about ill health can be more frequent when temperatures are below freezing and the humidity is very low. “The bottom line is that oxyfuels represent an enormous potential chemical burden. The issue is – how much do we know about them? Certainly, the amount of information we had prior to use [in 1988] wasn’t terribly extensive.”
In the EPA’s view, MTBE is no more harmful than many constituents of ordinary petrol, and probably safer than some. The agency has tried and failed to reproduce symptoms such as dizziness and nausea that are claimed to be associated with oxyfuels. In research carried out in 1993 at its research division in Research Triangle Park in North Carolina, a clinical study could find no difference between people exposed to levels of MTBE higher than those found at the petrol pump, and a control group. Another epidemiological study in the early 1990s at Rutgers University in New Jersey also found no link between ill health and the use of oxygenated fuels.
The oil industry and the EPA have studied MTBE extensively, and the results are not alarming, says Bob Drew of the American Petroleum Institute, the industry’s association. “We’ve worked real hard to understand the validity of the health complaints but all studies have turned up nothing.”
Finland is the only European country that manufactures oxyfuels for environmental reasons. The cold Finnish winters make cars particularly susceptible to high emissions of CO. Since 1991, oxyfuels manufactured by Neste, the state oil company, have accounted for 95 per cent of all fuel sold. The company also exports oxyfuels to Sweden. In the US, oxygenated fuel contains 2.7 per cent oxygen by weight, which is achieved by adding 15 per cent by volume of MTBE or 7.7 per cent by volume of ethanol. Neste uses an oxygen concentration of 2 per cent, which it achieves by adding 11 per cent of MTBE or, increasingly, another ether called called tertiary amyl methyl ether, or TAME. According to Neste, oxyfuels have lowered emissions of CO in Finland by between 10 and 20 per cent, and of hydrocarbons by between 5 and 10 per cent. It claims that no health problems have been reported.
Consumer choice
In Brussels, the president of the European Oxygenated Fuels Association, Jarmo Honkamaa, does not want oxygenates to be compulsory in Europe. He advocates the use of tax incentives to guide oil producers into making these products while allowing consumers a choice. In any case, he foresees an increase in the use of oxyfuels for other reasons. Countries such as Germany want to reduce benzene in petrol, he points out. If oxyfuels help hydrocarbons to burn more efficiently, then they could provide a way of maintaining a high octane content while reducing a fuel’s concentration of benzene.
For the moment, industry experts do not expect the European Commission to recommend making oxygenated fuel compulsory. Equally, it is unlikely to suggest a ban. In policy terms, oxyfuels are a small part of a much wider picture, but one still causing confusion and contradictory claims. In Britain, for instance, additive manufacturer Arco Chemical Europe is running a campaign called Clean Air Through Oxygen. It quotes the success of the American programme where “exhaust emissions in Colorado were reduced by 25 per cent”. But it fails to explain what it means by exhaust emissions.
The campaign has caught the attention of Jim Dowd, MP for Lewisham West, where air pollution and rising asthma cases among children are hot local issues. He wants the British government to investigate ways to introduce oxyfuels, including legislation and tax incentives for oil companies. “The government must urgently review this compelling evidence,” says Dowd. And the possible aldehyde emissions and health problems? “Well, nobody says it’s a perfect solution,” says Dowd.