Unleaded petrol: have we been told the full story?
By Richard Giles
One of the great shifts in attitude in this decade has come about in the promotion of unleaded fuel (ULP) to replace the dreaded leaded fuel. The issue of petrol and what to do about it has been the bane of environmentally minded people for half a century.
Concern about smog in the '60s and '70s led to the introduction of legislation in the USA and later other countries to control the emission of pollutants from vehicles.
Oil companies, confronted with the problem of city smog (mostly sulphur and nitrogen oxides) by public opinion and frustrated politicians, blamed the whole thing on too many cars. The actual figures on car ownership at the time show that while ownership in the USA was increasing steadily, the actual rate of smog particle emission was rising at almost four times the rate of car ownership.
There were two solutions. One was to limit the number of cars and driving hours on the road (which was political suicide at the time) or put something into cars to change emission levels. The second was the solution that the oil companies offered. Enter the catalytic converter â the environmental solution to all our woes!
The catalytic converter, oil companies said, would rid us of the unwanted compounds of sulphur and nitrogen from exhaust fumes. And lo and behold, the smog problem was solved. It worked. The monitoring of emission levels from motor vehicles over the last two decades has shown smog levels down in all major Western cities, despite the fact that car ownership has continued to rise.
Catalytic converters (CCs) play an important role in the introduction of unleaded petrol. The quality of oil supplies in the '60s was one issue. High grade, low sulphur, low nitrate oil was becoming scarce. It was a better oil for petroleum producers as less cost was involved in producing it. Producers, however, kept on turning out petrol from low grade oils with the resulting contaminants. This meant the levels of air pollution had slowly become worse until the rebellion against smog by legislators and consumers.
The chemical theory of catalytic conversion was known for years. Catalytic cracking is used at the higher temperature process of refining to make branch-chained hydrocarbons to form lubricants. Cracking and conversion are both catalyst processes. The process does not use up any of the chemical triggers. The initial set-up costs are extremely high, but once you have the refinery running, it's not expensive.
Fuel could be further purified, but oil companies would have to expend millions to set up new processes. A simpler way to do it would be to get car owners to pay for purifying and build a catalytic converter that fits into the car. That's what happened.
The small scale CC was designed to use similar principles to those used in refining. It was found that passing exhaust gases through a filter containing platinum and rhodium caused a catalytic conversion of oxides to other products. This works well until the platinum is coated. There were also by-products, some of which are very harmful, including hydrogen sulphide (rotten-egg gas).
Some consumer rights groups told US legislators at the time that the problem was not in the cars but in the use of low grade petroleum for refining. The refineries ought to clean up their act, they said. That never went any further. The age of catalytic converters was born. It became necessary to legislate them into all new model cars.
Now we have fuel with the pollution-causing oxides being removed by catalytic conversion. However, there was lead in all petrol to stop motor vehicle engines "pinging". Lead causes the CCs to lose working efficiency. After some time, the CC stops working because lead glazes the platinum in the device and bungs up the whole chemical process.
As well, converters work for only around 50,000 km, and their efficiency declines. The NSW Pollution Control Commission reported in August 1994 that CCs are likely to deteriorate much faster than was first thought, which may lead to increased carbon monoxide and nitrogen dioxide levels in cities rather than decreases.
They're also expensive, $300-2000 depending on which model car you drive. A lot of people will not voluntarily replace their converters. In fact, some will not even know it has to be done.
The next step is to introduce emission testing for cars and force the owner to replace their converter at great cost to themselves. In the USA a device has been developed and fitted to some cars that stops the vehicle from running after emission levels reach a certain level. They may become compulsory in the future.
The history of petrol throws light on why leaded petrol came to be. As the motor vehicle grew in popularity, it was costing oil companies more and more to refine petrol. They looked for ways to cut costs. Second, as there was a demand for more and more powerful engines, compression ratios were raised to get more power from the same engine size.
Eventually it came to the point where the new high compression engines would not run well on the lesser quality fuels being turned out. An engine under load would develop a condition called "pinging". This was caused by the fuel mixture in the engine firing before the right moment or burning too fast. This led to uneven running, stalling on hills and engine wear.
In the early 1920s a man named Thomas Midgie was among those looking to stop engine "knocking" or "pinging". He came up with oxides of platinum, silver and lead. Lead was the most successful. Midgie was able to get a compound called lead tetra-ethyl which slowed down the reaction to make fuel burn evenly. It was soluble in petrol, it broke down to lead at the high engine temperature, and it vaporised like petrol. So leaded petrol was born. It was widely used in World War II aviation fuel for quick take-offs.
Cars became bigger and bigger. Engines became more powerful until in the 1960s along came the environment as an issue. Cars became a number one target, and rightly so.
By the mid-1970s, lead in petrol was being identified as a culprit in environmental problems. Lead is a poison. It contributed to the collapse of Roman civilisation because lead in piping used to carry water through Roman cities and lead in drinking vessels was absorbed into the body.
During the 1980s, governments around the world began to test for lead in the environment and the human body. In Germany, the federal government decided to drop the lead content in fuel 0.5 grams per litre to 0.15 gm.
However, a report from German federal authorities stated after five years of testing more than 1000 people, "Since the changes observed are only of the order of statistical scatter, this indicates that lead from petrol did not contribute to uptake by ingestion through significant deposition on food and utensils as has been suggested. If it had been, greater and continuing decrease in blood levels in the community should have been observed."
Another interesting thing about lead that has not been given much publicity is that lead is baked at the operating temperature inside a combustion engine. The internal engine temperature reaches up to 3000 degrees C and, according to Professor Lowthur of London University, becomes like tiny bricks.
The lead falls from the tail pipe and settles on the road. It can be measured. Over three metres from the roadside, the lead measure drops off rapidly. Due to particle size its does not stay airborne and is less likely to be absorbed into the lungs. In the baked form, it is not soluble in the stomach's hydrochloric acid either.
So why the concern about lead in the environment and lead threats to children?
It's true that lead levels in blood are an indication of a risk to human brain function. The AMA has published articles showing at least 15 studies pointing to an association between lead exposure and intellectual performance.
Levels of lead thought to be safe last decade are no longer considered so. The new Australian health response level set by the National Health and Medical Research Council is now 15 micrograms per decilitre. The NHMRC wants to get all Australians below a blood level rate of 10 mcgms/dcltr.
Is leaded petrol the culprit that it's made out to be? In July 1993 the environment ministers of all states met with the then federal environment minister, Ros Kelly, and industry representatives to hammer out new standards on lead and plan the phase-out of leaded petrol (LP). They decided to raise the price of LP and remove lead from petrol progressively plus embark on a public education campaign on lead in the environment.
They were shown a graph of blood lead levels in the USA compared to the lead content in petrol. This graph appeared in the media in 1993. It showed blood lead levels dropping as lead was removed from petrol during 1976 to 1980. It shows what appears to be a strong correlation between the two (see Figure 1).
In the Canberra Times of March 26, 1994, the head of the Commonwealth Environment Protection Agency, Barry Carbon, claimed that the graph was "a trick" to force a rise in excise on LP. He went on to say that long-term data on lead reinforced his belief "that airborne lead is not a major source of lead in blood".
He further stated that the recommended use of ULP in pre-1986 cars not fitted with catalytic converters is risky and deserving of much more public scrutiny.
The article quoted from Professor Roger Perry of the London Imperial College of Science, Technology and Medicine, who has caused stirs in both the UK and Australia over issues involved in health and fuel. He claims emotional decisions have been made on leaded petrol. When visiting here in 1993-94, he claimed, "The whole issue of lead in petrol has been misrepresented by scientists and the press".
Perry went on to say that "the rise and fall of lead levels in the blood is related to a whole range of phenomena, lead in paint, in water, in dust, in solder, food canning and the like".
A graph reprinted here charts 76 studies on blood lead levels done worldwide from 1930 through to 1983 (see Figure 2). Looking at the second graph, you can see how the results from 1976-1980 were used at the Roundtable Lead Conference in July 1993 to produce a distorted picture of the link between LP and blood lead levels. The full graph shows no correlation between leaded fuel and blood lead.
The question is, why was the conference shown misleading figures? Who made the decision, and what were their motives? And how did they get away with it?
Were Ros Kelly, state environment ministers and petroleum industry reps all involved in some scam to phase out lead and boost petrol prices, or were they just innocent parties in some fraud perpetrated by someone else?
There are many unanswered questions. Now the public and the environment movement are caught in the same story. We all believed religiously that it was in our best interests. We've saved our children from leaded death! All those beautiful petroleum industry posters of little girls dancing in fields of flowers safe from leaded petrol!
What do Australian figures on blood lead levels show? A 1993 Victorian study was done on 252 children from both country and city, ranging from infants to early teens, who visited hospital from June to December 1993. Only three â 1.2% â showed lead levels above the 15 mcgm/dcltr standard. Of these, one was an intellectually disabled child with an eating fixation. The other two were found to have ingested lead orally from local sources. None had high lead levels linked to airborne lead (see figure 3).
The threat of vehicle-derived airborne lead to children's IQs must also be seen from another perspective. The total amount of lead in fuel in Australia peaked in the early '70s. By 1990 the amount of lead in fuel had declined by 40% and then again by over half to 1995 (on January 1, 1995, the amount of lead in petrol was lowered by 33%). These levels indicate that any threat to young children from airborne lead is less than 30% of what it was in the early '70s. People who are now around 20 years of age have been exposed to one and a half times more lead than kids today.
The non-lead ingredients added to petrol to stop pinging and maintain octane ratings are known as aromatics. They are from a category of organic substance known as VOCs â volatile organic compounds. These include benzene, toluene (methyl-benzene), dimethylbenzene, xylene and mesitylene (1,3,5 triethyl-benzene). All are petroleum derivatives. Some are toxic, others are extremely toxic.
Xylene has recently been ordered removed from all marker pens due to its extreme toxicity. Benzene is rated as a carcinogen. Toluene in pregnant women has recently been shown to cause birth defects. A standard text, S. Baum's Introduction to Organic Chemistry, says, "Repeated exposure to benzene leads to a progressive disease in which the ability of the bone marrow to make new blood is eventually destroyed".
Benzene has been linked to cancer and leukaemia in numbers of studies. As long ago as 1977, the Italian Ramazzini Foundation for Oncology and Environmental Science established that benzene was a powerful carcinogen. It also found subsequently that all aromatic hydrocarbons in fuel cause increases in malignant tumours in animals.
Professor Cesare Maltoni and Morando Soffritti have conducted tests on exposure to all fuel additives. In August 1994 Maltoni addressed the Clean Air Conference run by the CSIRO in Sydney. He presented evidence that benzene is one of the most dangerous industrial carcinogens known. He stated that the risks from benzene and other aromatics have been seriously understated in view of the scale of motor vehicle pollution. More than 400 million cars worldwide burn 600 million tonnes of fuel a year.
Maltoni said he and other scientists were "alarmed" at the way the slogan "No lead, no worries" had generated a "warped" situation in which additives in petrol are favoured, not because they are safe, but because no real research has been done on them.
At the same conference, Dr Simon Wolff of the University College, London School of Medicine, expressed his concerns on benzene. He had set out to find an explanation for ten-fold increases in childhood leukaemia in some population groups in the UK. He found that areas most at risk were newer, middle-class suburbs and townships with high levels of car ownership. He found epidemiological evidence that benzene, petrol vapours and exhaust gases can cause lymphatic cancer and leukaemia of the types common in children. He speculated that children require far less exposure to develop cancer than do adults. Those in areas of high traffic density and who used the car more were at bigger risk. Wolff also found that the other ULP aromatic additives also produce benzene under combustion.
He concluded that Britain's present plan to cut benzene concentration in air from 5 parts per billion to 1 ppb were not enough for children. He suggested that benzene levels had to be cut 50 or 100 times, not just by one fifth. The World health Organisation and the USA EPA estimate that for every 1 ppb benzene we can expect 8« cases of myeloid leukaemia in a population of one million.
What level does Australia require? The Victorian EPA has a level of 30 ppb as safe. In the USA, 10 ppb is set as the safe level. The Victorian EPA in a 1992-93 study of benzene levels found rates which exceeded its safe levels in inner Melbourne suburbs. It also found higher rates in service stations and inside vehicle cabs.
Dr Michael Dawson of the University of Technology, Sydney carried out tests in inner Sydney in 1994 showing levels between 4 ppb in summer and 7.7 ppb in winter. He found that at peak hour it climbed as high as 25 ppb. CSIRO tests in Sydney found an average of 2 ppb benzene and registered 35 other airborne toxins (see figure 4).
The Shell company's Dr Malcolm Brown argued at the same conference that benzene levels in Australian cities were low and falling as more new vehicles coming on the road had catalytic converters. He quoted the Shell study on benzene levels in Melbourne which showed an average benzene concentration of 2-3 ppb.
It emerged in that conference that Australian EPA authorities do not monitor benzene levels here. A number of speakers heavily criticised the EPA for a lack of commitment to obtaining data on benzene. A new study in Australia carried out by the Australian Committee on Vehicle Emissions will look at national levels for total hydrocarbon emissions over 1994 to 1996. It now plans to include benzene levels, due to public pressure, according to project director Peter Anyon.
Back in 1983 the Committee for Energy Resources in Victoria was asked to make recommendations on banning lead in petrol. Dr David Warren was the chief scientific adviser to Energy Resources and a research scientist for the Department of Defence. His report concluded that there was not sufficient evidence to show lead in petrol was a significant health risk. His chief reason was that all evidence showed that exhaust lead from cars was not airborne.
In the same year a report from Dr Allan Bell, director of the NSW Health Department, circulated in Australia stating that if lead is to be removed from petrol, the replacements needed to maintain octane ratings were benzene, toluene, dimethylbenzene or mesitylene, all of which are ring compounds and suspected carcinogens. He concluded there was little evidence on the risks from lead and more on the dangers of cancer from these unleaded petrol additives.
Dr Warren's report was read to an empty house in the Victorian parliament in 1983. The decision to replace lead in petrol was already party policy.
In a speech to members of the automobile club of Victoria in February 1993, Dr Warren said, "In fact this stuff [aromatic additives] appears to be so dangerous, potentially lethal, that I urge you not to use it in any car not fitted with a catalytic converter. Don't use it in your mower, chainsaw, whipper snipper or outboard, and don't wash parts in it, and if any gets on your skin wash it off immediately. Avoid the fumes when refuelling and don't allow anyone near the exhaust, particularly when the exhaust is cold. Remember that catalytic converters don't work until they reach some 400 degrees."
The use of a whole mixture of aromatic additives in petrol may leave us with a heritage of increased cancer and leukaemia amongst adults and children. Because of its ability to be absorbed even through skin contact, benzene is a high risk substance. And the other aromatics convert to benzene in combustion.
Service stations then become high risk areas. ULP and super ULP are dangerous in the air. Super ULP (which has over 30% aromatics) is so risky an all-party committee in Britain recommended its banning in 1994. It stated, "The potential health hazards resulting from the excessive aromatics used ... outweigh any possible benefits from the reduced lead". In April 1995 the British government announced that super ULP is to be progressively withdrawn over the next two years.
What to conclude? There seem to be flaws in the scientific information demonstrating that lead in petrol is a threat to people. The aromatics added to petrol to make up for the loss of lead constitute a threat in themselves. It seems that the aromatic additives â benzene, toluene, xylene, mesitlylene and dimethylbenzene may be as risky to health or even more dangerous than lead additives. In particular, benzene is rated as one of the most toxic and carcinogenic chemicals in atmospheric pollutants.
The role of catalytic converters in the removal of toxic airborne pollutants is also under question. It seems that catalytic converters may have much less of a useful life than we have been led to believe.
What to do? There are a number of alternatives for dealing with the problem. The first would be the use of ethanol or methanol as substitutes for aromatic additives. Fuel in some South American countries has up to 25% ethanol added successfully. The by-products of ethanol and methanol are water vapour and carbon oxides. Nitrides and sulphides are not produced.
The sugar industry in Australia could provide the sugar for ethanol production. A very tiny amount of lead could be added to reduce knocking. The problem with this solution for the oil companies is that they do not own the sugar industry, and therefore there's no money in it.
In the USA, a fuel called reformulated gasoline was introduced nationally from January 1. It has oxygen-containing MTBE (methyltertiary-butylether) an antiknock compound that breaks down to water vapour and less dangerous exhaust gases (although recent evidence from Alaska points to increases in respiratory problems after MTBE was introduced into fuel there). It has been used in Colorado state since 1988.
In Germany a new fuel called ecological gasoline is being introduced with oxygen-containing substances and much lower proportions of aromatics. It will bring down the amount of benzene in exhausts by 42%. It's referred to as oxyfuel. The cold northern European countries like Finland and Sweden use oxyfuel containing up to 8% by volume of oxyfuel.
In Australia we are still caught up in the campaign to phase out lead and take old cars off the road in the mistaken impression that they are more dangerous to the environment than new cars. Meanwhile, leaded petrol has been reduced to 0.2 gm/l of lead, but it contains more than 25% aromatics!
What's happening is that even the lead in LP is being replaced by benzene and its nasty brothers. This is an environmental disaster for cars made before 1986 with no catalytic converters fitted. More and more benzene is being spewed out of pre-1986 cars and poisoning children. In addition, benzene is being added by cold vehicles with inefficient CCs in their warming-up period and by CCs that are failing due to age.
A recent survey of the contents of ULP and LP around Australia done by Noel Child, consulting engineer and lecturer in environmental engineering at University of Technology, Sydney, and Dr Michael Dawson (published March 1995) showed as much as 36% aromatics in super ULP, 28% in ULP and 29% in premium leaded petrol.
The decision to phase in ULP with a high aromatic additive content could well be a disaster for Australian health. The results will begin to show up over the next 20 years as today's younger generation grows up with benzene-saturated air in cities.
Other countries are showing the way with alternative approaches to fuel additives. The facts on leaded and unleaded petrol need to be aired in the community now for wise decisions to be made, not in 20 years when a new generation may die of new cancers.
@note = Sources:
@note = "Hushed Up Dangers", Explore, Vol 5, No 5/6, 1994.
@note = S. Grose, "Choose Your Poison", Canberra Times, March 26, 1994.
@note = "Scientists Debate Carcinogenic Risk of Cars", Australian, August 13, 1994.
@note = G. Allum, "Is There an Old Car in Your Future?", Restored Cars, No 104/1993.
@note = D. Maddock, "Leaded V Unleaded Petrols", Australian Health & Healing, Vol 14/1.
@note = C. Simons, "The Lies of Unleaded Petrol", Nexus, April/May, June/July 1995.
@note = P. Sawyer, Green Hoax Effect, Groupacumen Publications, Victoria, 1990.