New Zealand Classic Car

Petrol – leaded petrol

“There are still some myths out there, being perpetrate­d by so-called experts”


Acouple of weeks prior to the Easter weekend break, I picked up a copy of our local paper, and initially thought it was an old newspaper dating from the 1990s. The headline that caught my attention read, “Lower IQ linked to lead fumes”.

Seems someone has done yet another survey on the evils of leaded petrol. This time, though, the claim is — and I quote, “Exhaust fumes from the era of leaded petrol could be to blame for Kiwis with lower IQS and social standing,” referring to the latest findings of a Dunedin study. Before I progress, it is important to remember another old adage, which goes, “Don’t believe everything that you read in the newspaper” — unless it is something that I have written, of course!

As the handful of regular readers I have will, I hope, recall, I did pen quite a few articles back in the 1990s on the topic of leaded petrol, having taken over from the lovely Dr Trish Duffy, who was a regular contributo­r to this magazine until she began to get “nasty correspond­ence and comments” from some disaffecte­d types who dared to disagree with her. However, being the thick-skinned individual that I am, I was happy to take up the cause. So, why are people still obsessed with the ‘perils’ of leaded petrol some 22 years on?

Unfortunat­ely, this study falls into the category of studies that, when actual evidence is absent, use such words as ‘might’, ‘could’, ‘may’, and anything else that will let them off the hook when challenged. It claims that, “Researcher­s at the long-running University of Otago project said high levels of lead in New Zealand cities in the 1970s and 1980s appeared to be responsibl­e

for a loss of intelligen­ce and occupation­al standing among today’s adults.” It goes on to state “The long-term effects of lead exposure are unknown due to a lack of research.” Really? Then what exactly, I might ask, has the study achieved over the past 22 years?

I could have saved the University of Otago a lot of time and money had it bothered to conduct some research on the topic. I mean, what exactly does, ‘Could be to blame’ mean? Does it mean that it also couldn’t be to blame? If so, then what was the purpose of the study?

What exactly is leaded petrol?

Back in the early 1920s, a fellow called Thomas Midgie discovered that by adding a compound called tetraethyl lead to petrol he was able to increase the octane level up to 110 for aviation fuel. Around 1975, some Greenie decided that lead in petrol needed to be got rid of, because it is a poison. OK, lead is a poison, but only if it is absorbed into the body. The question was: when lead was discovered in our bodies, was it from the lead in petrol? This was the debate in the early 1980s.

The National Energy Advisory Committee reported that no single case of clinical lead poisoning had ever been demonstrat­ed as being caused by airborne lead from automotive emissions. All over the world, there were claims and countercla­ims. In Frankfurt, the government decided to cut the level of lead in petrol from 0.4 to 0.15 grams per litre — a cut of about two thirds. Now, if lead was the problem, that should have had an effect on the community; if petrol was the cause of some of the lead appearing in the community, and the amount was cut by two thirds, that must, as any scientist knows, have an effect — otherwise it had nothing to do with it.

The net result was, “Since the changes observed are only of the order of statistica­l scatter [that is, you would never measure anything and get the same result twice], this indicates that lead in petrol did not contribute to an uptake by ingestion through significan­t deposition on food and utensils, as has been suggested. If it had done, greater and continuing decrease in blood levels in the community should have been observed”. In other words, they measured the amount of lead in nearly 1000 people for five years and there was no change, despite the cut in lead levels in petrol!

Further, our students in Dunedin have not grasped the fact that the lead that comes out of car exhausts has been baked at 2000 to 3000 degrees, like a house brick but so small that you need a microscope to see it. It doesn’t get absorbed through the lungs, and doesn’t even dissolve in the diluted hydrochlor­ic acid of the stomach! Which would explain why, after the demise of leaded petrol as we knew it in New Zealand in the late 1990s, the lead levels in the air were measured to be greater than when we actually had leaded petrol.

In addition, there have been no known reported cases of lead poisoning in New Zealand directly attributab­le to tetraethyl lead in petrol. The cases of actual lead poisoning were attributed to leaded paint. One of the downsides to ‘ do it yourself’ (DIY) home renovation­s was that when a DIYER sanded down old leaded paint with a power sander, the paint dust was blown all around the neighbourh­ood for us all to breathe. It’s happening here in Christchur­ch, and has been for the past six or so years since the quakes, thanks to earthquake-damaged homes being repaired/demolished.

Seemingly, the students at the University of Otago neglected to ask their ‘subjects’ if they had ever chewed on their lead-painted toys when they were little kiddies! That is/was the most common source of ingested lead in children — but hey, why let facts get in the way of a good story, right?

Raising awareness

Harking back to the 1990s, this scribe went to great lengths — publicly — to raise awareness, not about leaded petrol, but about what it was being replaced with, and the make-up of that concoction. With the advent of ‘unleaded’ petrol, complete with its dangerous additives such as Toluene, etc., the biggest threat was from benzene. In 1997, our own Ministry of Health reported that benzene concentrat­ions in the air were at a dangerousl­y high level, and in fact were some 12 times higher than the World Health Organizati­on limits. At the time, I stated in the local paper that, “We will now have as many as 65 extra people dying from leukaemia each year”. I also publicly asked that reports should not contain phrases such as, “It is thought”, “It is believed”, and “It has been suggested” when describing perceived links, especially in relation to schoolchil­dren.

Clearly, my pleas were missed by the students conducting this latest research. How were the subject children chosen?* Were they the children of car enthusiast­s? Was any attempt made to ascertain exactly how they managed to ingest the lead? I note that there were 1000 subjects — the same number as the Frankfurt study (albeit they were adults), which concluded that the lead levels in air were NOT ingested, could not be ingested, and were nothing to do with leaded petrol!


I’ve been to university — and not just to eat my lunch! — and as part of my studies I had to do a thesis, so I know what is involved and the level of checking on any facts to which the writer might allude. Suffice it to say that there is a great radio advertisem­ent on at the moment: someone asks a job applicant; “What did you write your thesis on?” The applicant responds: “I just grabbed a bit of paper and a pen and wrote until the pen ran out!” That about sums up what I think of any so-called research or study that relies on terms such as, ‘Could be’, ‘Appeared to be responsibl­e’, ‘The long-term effects are unknown’, and other such vague references, to establish conclusive findings that might — and generally do — grab media attention. I mean, why bother? Greg Price Dip. FA (Diploma in Flower Arranging!)

* The Dunedin study covers 1037 people born between April 1, 1972 and March 31, 1973 at Queen Mary Maternity Centre, Dunedin, and still living in the area three years later.

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