The Impact of Exposure to Leaded Gasoline Was Horrific: Will We Say the Same in 2050 About the Impact of PM2.5 Exposure?

An article in the Proceedings of the National Academy of Sciences (login required) has documented the devastating impact caused by the use of leaded gasoline.  The study estimates that more than half of Americans alive in 2015 had been subject to unsafe blood lead levels as children.  The study further estimates that the impact of these elevated blood levels was a net loss of 824,097,690 IQ points as of 2015.  I have to acknowledge that this estimate seems to reflect a major problem with false precision, but you get the point.

Why does this matter in 2021?  There are several reasons.  First, it demonstrates just how big an impact responsible environmental regulations can have.  Notwithstanding problems with lead in pipes, exposed in the Flint case and certainly not to be underestimated, the figures in the article show a huge drop in child blood lead levels resulting from the elimination of leaded gasoline.

There’s also an important lesson to be learned from the elimination of leaded gasoline.  I’ve written numerous times on the issue of regulation under uncertainty.  As all of us older environmental lawyers know, it was the decision in Ethyl Corp. – which involved a challenge to EPA’s regulations on leaded gasoline – that is the foundational case supporting EPA’s authority to regulate under uncertainty.

When EPA first regulated leaded gasoline, the public health community believed that there was clear evidence of the dangers it posed.  However, that evidence was criticized as not providing a sufficiently certain basis on which to regulate.  Does this sound familiar?  It should.  The same debate is being replayed now in the context of EPA’s review of the National Ambient Air Quality Standard for PM2.5.  The Clean Air Scientific Advisory Committee, as reconstituted under the Trump Administration, and EPA Administrator Wheeler basically took the same position as Ethyl Corp. did 45 years previously.  They argued that the available epidemiological evidence is not sufficient to demonstrate a causal link between PM2.5 levels and increases in morbidity and mortality.

I just hope that, when the public health accounting on PM 2.5 is done sometime around 2050, we’ll be celebrating the reductions in morbidity and mortality from EPA’s careful reductions in PM2.5 levels, rather than mourning missed opportunities to save lives and improve public health.

One thought on “The Impact of Exposure to Leaded Gasoline Was Horrific: Will We Say the Same in 2050 About the Impact of PM2.5 Exposure?

  1. Yes, let’s hope for the improvement, but an empirically valid accounting would be far from straightforward and probably cost too much to accomplish. Lead dose- response and exposure situations were a relative “no brainer” ( sorry, poor choice of words). By contrast, PM2.5 exposures involve all sorts of complications, including but not limited to particle type (is it asbestiform “needles” or adsorbed PAH or metallic dust?) and the variety of sources..For example, was it fugitive pesticide residues, multiple convergent industrial emissions from point and area sources, and/or occupational exposures? I think it best to spend the money to get the overall reductions and reap the overall benefits without expecting detailed accounting.

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