As the insider who knew the most about gasoline and lead and poisoning I can tell you for sure how my thinking went. When I was first given the job of technical services manager for BP Oil in NZ that included product specification and design including emissions and associated issues. Benzene, lead and other things were the main issues. There was no benzene limit. Benzene causes myeloid leukaemia. I introduced a 5% by mass limit to get control of the situation straight away. That wasn't my final thinking on benzene, just the start. I thought lead probably wasn't much issue as I thought it would be so diluted that it wouldn't matter. But I got kilograms of scientific data and waded through it all including Needleman IQ studies. Bloody hell!! I soon changed my mind.
The amount of lead in people was commonly about 15 micro grams per decilitre of blood (as I recall 40 years later) with clinically evident lead poisoning being about 60. I thought that meant sub clinical poisoning as the gap was so small. That was 1983. Sources of lead were paint, water, toys, and others but petrol contributed about quarter of it. I calculated the economic harm by reduced intelligence. That's easily calculated because IQ versus income is well known. From Needleman and co, the IQ damage due to lead in petrol was about 1/4 of an IQ point. That might not seem much as people have 100 of them. But if you calculate the cost it far exceeded any possible benefit from cheaper petrol. I'd have to redo the numbers to be accurate on the cost of lost intelligence but it was about $10,000. That buys a lot of petrol.
Then there was the hazard for motor mechanics dabbling in grey paint which coated valve trains/rocker arms back in the day, with lead coating pistons causing octane requirement increase meaning higher octane petrol was needed = more expensive petrol. Carcinogenic lead scavengers were needed to reduce that = more pollution. Exhaust pipes were coated in lead causing hazard to people working on those which was common as exhaust pipes had to be replaced frequently back then.
Worse still, I think the purported benefit was false in that adding lead acted like a spark retarder which avoided knock but reduced engine efficiency. Shell introduced Formula Shell in April 1986 which included Spark Aider which I predicted would lead to knocking when hot weather started in June. It did. Shell had a huge disaster and pulled the product. Cost them £40 million or so. They should have increased octane number by 2 and people would have noticed increased performance. But they didn't = big failure.
Engine oil was polluted by lead and muck meaning oil changes had to be more frequent.
So for no real benefit, to customers or BP, and much damage to vehicles and brains, decades of lead were included. Associated Octel and other lead suppliers made $ millions. No wonder they lied to maintain sales.
One problem with unleaded petrol was that exhaust valve seats were not hardened, so without lead, valve seat recession was a problem, as the lead acted as a cushion. Engines had to be designed with hard valve seats.
Catalytic converters were poisoned by lead so USA got rid of lead early as smog was a big problem especially in Los Angeles.
Finally lead was eliminated as all cars were replaced. Meanwhile lead was reduced to minimize harm.
I don't believe oil companies knew the problem was as bad as it was as I was the one designated to sort out the issues and other emissions and what to do. I was promoted to London to do that job because Ken Gilson who was in charge of Technical Services Branch in London liked my ideas and appointed me to do it in late 1985 having seen what I was doing in NZ. I had explained my ideas to him during a visit to NZ.
I also wanted 98 RON petrol for high performance cars and 91 RON for round town cheap-skates who just want cheap motoring. The plan had been to have a single Eurograde 95 RON. That would give motorists what they want and make lots more money for BP.
Mqurice |
