For example:
- If you're a smoker, your exposure to the hazardous substances in cigarette smoke is sky-high. The risk to your health of being a smoker is so high and so clear that societies spend millions of dollars to try to convince people of the risk.
- If you're living with a smoker, but not a smoker yourself, then your exposure is lower, but still high enough to be actionable. So we see indoor smoking bans and 2nd hand smoke information also included in anti-smoking campaigns.
- If you're walking down the sidewalk and pass by a smoker for three seconds, you're still encountering the exact same hazard, but your exposure is so low that the risk is not really actionable. It's not like we see big public campaigns about crossing the street to avoid the risk of 3 seconds of exposure to second hand smoke. That's because the risk isn't there.
- Someone smoking in their house 50 miles from you is obviously zero risk to you at all, even though the hazard still exists.
You can see the same kind of pattern everywhere: car exhaust is the same hazard everywhere, but whether it's a risk worth actioning depends on whether you live in a dense urban center, or next to a busy freeway, or out in the exurbs.
So back to the plastic stuff. The study authors were claiming that the level of risk was high enough to justify everyone in the world throwing their utensils away and buying brand new ones. When it came out that the exposure factor of their "risk = hazard * exposure" formula was actually off by a factor of 10, they... stuck with the exact same story? I don't know, man. The original claim was below the acceptable risk threshold, and now it's even ten times lower than that. Surely that has some impact on the level of risk? Does this drop the risk from "smoker" to "passing by a smoker for 3 seconds"?
The distinction matters when deciding how much effort mitigating this risk requires: should I throw everything out right now, or just buy something else when my current ones wear out, or is the risk actually so low that it really does not matter? If I replace them, what is the level of risk of the things I replace them with? Should society put in the effort to ban these chemicals? What are the pros/cons of that? Are the risks mitigated worth the costs?
The authors' refusal to acknowledge this really makes me doubt that their conclusion is not affected by some kind of bias. The jury's still out, sure, but I'm not yet sold on their risk claims.
And it's trivial to replace with materials that don't have that risk. For a couple bucks you can remove fire retardants from your food. Why wouldn't you?