Math Error Behind Plastic Panic

I recently encountered an Atlantic article titled, "Throw Out Your Black Plastic Spatula," with a blurb elaborating, "It's probably leaching chemicals into your cooking oil."

Oh, the horror!

I have been using the same black plastic coffee maker for at least 15 years and a set of black cooking utensils for at least a decade. Not being dead or unwell after such recklessness, I kept all of them, and decided to check on this again later.

I'd either look at the research myself or to see if someone in the field confirmed or denied that there was really something to worry about.

I felt quite comfortable that the latter would be the case.

Folks from the States might also want to watch this just to see what a real news interview about science looks like.

Indeed it is.

Canadian outlet CBC News interviewed Joe Schwarcz, director of McGill University's Office of Science and Society on the matter. I thought Schwarcz did an excellent job of explaining the findings -- Flame retardant chemicals do indeed leach out of some black plastic cooking utensils. -- and, more importantly, putting them into context: The amount that leaches out would -- even using the conservative methodology of the paper -- be well under a tenth of the reference dose:

The United States Environmental Protection Agency defines a reference dose (abbreviated RfD) as the maximum acceptable oral dose of a toxic substance, below which no adverse non cancerous health effects should result from a lifetime of exposure. It is an estimate, with uncertainty spanning perhaps an order of magnitude, of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. [links omitted, bold added]

I guess that explains why I'm not dead or unwell.

My snark aside, the basis for the panic turned out to be a miscalculation in the paper: The exposure from using the utensils was overestimated by a factor of ten, giving a number still below the reference dose, but uncomfortably close to it.

Schwarcz also addresses the prima facie reasonable objection that we should avoid all such hazards when he notes that steel utensils, for example, might leave trace amounts of poisonous metals in our food.

It would seem that as our technological ability to detect tiny amounts of chemicals improves, we are forgetting the principle -- also cited by Schwarcz -- that the dose is the poison.

It is still too soon to tell if this panic will blow over, as it seems so far to have done -- or if the incorrect conclusion will get recycled and reused as part of an environmentalist crusade against plastic.

-- CAV