You know what is really impressing me about Neil deGrasse Tyson’s Cosmos? That he doesn’t hesitate to draw connections between science and how we live our lives — there is an implicit understanding that science has become fundamental to how we see the universe. Last night’s episode was no exception. What started as an explanation for how we know the age of the earth (4.55 billion years), as established by the rigorous measurement of the ratio of lead to uranium in meteorites by Claire Patterson, became an exploration of health and the misuse of science, as personified by Robert Kehoe.

Patterson was an expert in analyzing trace elements; Kehoe was a doctor who was in the pocket of the petroleum industry. Patterson saw rising levels of lead in the environment as a consequence of its use as a fuel additive; Kehoe was getting paid to sow doubt. Patterson focused on the effects of environmental lead on human health; Kehoe was more concerned with the profit margins of industry. The campaigns for lead additives in fuel resemble the abuses of science used to promote cigarette smoking and to fight actions to curb greenhouse gases. I dug up a review from the 1990s by Jerome Nriagu, and it also reminded me of something else: the damned limited perspective of proper science by the non-scientists in the skeptics movement.

Here’s the first part of the abstract.

In 1925, Robert A. Kehoe enunciated a paradigm predicated upon categorical distinction between expectations and conjecture (“show me the data” mentality) from hard scientific facts on exposure outcomes. It led to a precedent-setting system of voluntary self-regulation by lead industry as a model for environmental control and implicitly signaled the level of industrial responsibility for lead pollution.

“Show me the data”? What could be wrong with that? Isn’t that what we’re supposed to do?

What that attitude fails to do, though, is to recognize degrees of uncertainty — that we don’t have absolute knowledge, but that all of our information comes with two measures: here’s what we’re pretty sure is true, and here’s a measure of variability or uncertainty to give you an idea of the bounds of our confidence. So Patterson measured the age of the earth at 4.55 billion, ±70 million years (that bound is now down to around 20 million years). The uninformed or the devious can choose to emphasize that uncertainty of 70! Million! Years!, which is a very long time, while the scientists are looking at the 4.55 billion part.

That is the Kehoe Paradigm: emphasize the noise in the data. Talk about nothing but the variability. Make it sound like the scientists are baffled by their own data, simply because they are aware of the limitations of their knowledge.

Cosmos was relatively gentle with Kehoe; he was clearly the villain of the story, but it didn’t make a big deal of the fact that he was a paid hack of the oil industry who was hiding the evidence in the name of profit. Well, not as big a deal as they could have, anyway — Kehoe was enabling world-wide environmental poisoning.

Here’s the rest of that abstract.

It combined a cascading uncertainty rule (there is always uncertainty to be found in a world of imperfect information) with a highly skewed cost-benefit concept (immediate benefits of tetraethyl lead additives must be weighed against possible future health hazards). Many studies were funded by the lead industry to develop a theoretical framework for the paradigm which served as a strong defensive strategy against lead critics. It resulted in an unfettered growth in automotive lead pollution to over 270,000 tons per year in the United States and 350,000 tons per year worldwide during the early 1970s. Clair Patterson is credited with being the first person to mount an effective challenge against the Kehoe paradigm, and with his success came an upsurge of activity and attention to the risks of environmental lead pollution on public health.

That should sound familiar: multiply uncertainty, and balance it with a biased cost-benefit analysis. How libertarian!

Maybe not all of you remember the 1960s-1970s, but I do: I remember the ads everywhere touting one brand of gasoline that put a “tiger in your tank!” I didn’t know at the time that the tiger was tetraethyl lead, and that a rather nasty environmental toxin, in addition to the carbon monoxide and carbon dioxide, was pouring out of everyone’s exhaust pipes.

The heart of the Kehoe Paradigm was to first piously state that if it could be conclusively shown that tetraethyl lead was a public health danger, then of course the lead industry would stop, as the only rational and morally acceptable response. But then he would go on to argue that it wasn’t conclusive at all, yet — so the default response should be to allow industry to continue to profit until the consequences to public health were undeniable. And this neglect of responsibility was all neatly wrapped up in the claim that it was the “scientific” way of thinking — that somehow, science only deals with absolute truths and that you can’t draw scientific conclusions until every detail is knitted up with complete certainty.

The signals that this was all wrong should have been recognized early. Science is about a gradual convergence on a truth, and we make provisional statements about reality that are always subject to revision. If the preponderance of evidence leans one way (and that breathing tetraethyl lead was bad for humans was rather obvious), the onus is on dissenters to provide strong counter-evidence…not to natter on about what the scientists don’t know for sure. Need I point out that this is also familiar creationist strategy, that rather than actually providing a coherent theory and supporting body of evidence, they’d rather go on and on about our areas of uncertainty?

But also there was another obvious problem. Kehoe was bought and paid for.

Robert Kehoe and the lead industry were very closely entwined in more ways than just the theory and practice of occupational health protection — the lead industry built and equipped a laboratory for him, paid his salary (minus the $1.00 per year he received from the University of Cincinnati), and financed most of his research. The return for the symbiosis included an unprecedented control on research and knowledge about occupational and environmental lead hazards and the stifling of environmental pollution control programs in the United States for many decades.

I’m sure you’ll be pleased to know that this villain lived in prosperity and prestige to the ripe old age of 99, dying in 1992, after a lifetime spent making sure that Big Oil could freely poison all the children in the country.

Another approach of the Kehoe Paradigm was to emphasize “thresholds”. A little bit of poison is OK; it’s only when it reaches some particular threshold that it becomes bad for you, and as long as the industry doesn’t cross that line, it is doing you no harm. In the case of lead, Kehoe argued that the threshold was 100 µg/m³ — which is a hell of a lot of lead. It’s also not true that there is a “threshold”. I recall getting harangued by my old genetics professor, George Streisinger, who had been testifying for the Downwinders (people who had been exposed to fallout from nuclear tests), that there is no such thing as a threshold for radiation exposure — it’s a continuous sliding scale of increasing probability of damage with increasing dosage. But if you draw an arbitrary line, sanctify it with the label of science, and say anything below the line can’t hurt you…well, Science says it’s safe, so it’s fine. Unfortunately, the evidence doesn’t say any such thing.

Patterson really was a hero, and I was happy to see Cosmos give the man credit. He used evidence to fight against Kehoe; for instance, he did measurements (as shown on the program) to show that pre-industrial levels of lead were 0.0005 µg/m³, in contrast to the modern American levels of approximately 1µg/m³ — we were breathing in 2000 times as much lead now. To argue that the lead industry was not making a massive contribution of poison to the environment was raw nonsense.

He also found fault with the whole “threshold” idea. The clinical responses to acute lead poisoning were just an extreme on a continuum — he speculated that “below the then accepted threshold concentration there were some effects which clinically might be difficult or impossible to detect or ascribe to their real cause.”

But he also emphasized the problem of bias. “You can use the data to justify your purposes. If your purpose is to sell lead alkyls, then you look at these data one way. If your purpose is to guard public health, you will look at this data in another way, and you will reach different conclusions.” Ataxia, coma, convulsions, and death are easy to diagnose, so using those as markers for a threshold may be convenient, but it ignores the subtle neurological effects, which might be important, too. Perhaps it isn’t surprising that crime levels have been in decline since lead emissions were limited (this is another case of a purely correlational measure, but let’s not ignore it — we’ve removed a neurological poison from the atmosphere, and simultaneously see a shift in human behavior? Reasonable mechanism, measurable response, worth pursuing more).

Patterson testified before congress, as shown on Cosmos, and really chewed out industry and Kehoe for their misappropriation of science.

It is clear, from the history of development of the lead pollution problem in the United States that responsible and regulatory persons and organizations concerned in this matter have failed to distinguish between scientific activity and the utilization of observations for material purpose. [such utilization] is not science…it is the defense and promotion of industrial activity. This utilization is not done objectively. It is done subjectively. … It is not just a mistake for public health agencies to cooperate and collaborate with industries in investigating and deciding whether public health is endangered—it is a direct abrogation and violation of the duties and responsibilities of those public health organizations. In the past, these bodies have acted as though their own activities and those of lead industries in health matters were science, and they could be considered objectively in that sense.

Patterson eventually won on this one specific issue, and we’re no longer burning tons and tons of lead. I wish I could say he’d won on the broader principle, though, because he didn’t — the Kehoe Paradigm is still the standard pseudoscientific approach used by industry to justify great evils. For instance, CEI is arguing that we shouldn’t expand regulation of industrial chemicals just because of a little ol’ spill in West Virgina with a slew of half-truths…including the claim that MCHM has “low toxicity”. It’s the threshold argument again.

We’re still trying to unravel the tangle he made of science policy, though. Kehoe’s Paradigm lives on at various right-wing think tanks, for instance, the Heartland Institute, where the headline that greeted me when I just visited was Climate Change Reconsidered, which concludes that the human effect is likely to be small relative to natural variability, and whatever small warming is likely to occur will produce benefits as well as costs. Change climate change to environmental lead, and it could be straight from Kehoe, and is just as honest.

At least Cosmos is making an effort to show that good science matters, and matters everywhere in your life.

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Nriagu JO (1998) Clair Patterson and Robert Kehoe’s paradigm of “show me the data” on environmental lead poisoning. Environ Res. 78(2):71-8.