What I've tried to do while parenting is focus on relative risks and mitigate the worst ones.

For kids the major mortality risk is "unintentional injury" (https://www.cdc.gov/injury/wisqars/LeadingCauses_images.html). This is further classifiable into categories that represent risks we can mitigate (https://www.cdc.gov/vitalsigns/childinjury/index.html): car crashes, suffocation, drowning, poisoning, fire, falls.

This means you can dramatically improve top-line safety just by doing stuff like

* take fewer car trips and always carefully adjust the fit of carseats

* follow best practices for safe infant sleep (alone, on the back, in the crib)

* be careful around water, introduce swimming lessons as a layer of protection against drowning at ages 1+ (AAP recommendations changed recently on this as evidence changed)

* keep medicine and poisonous cleaning supplies out of reach or out of the house

* keep smoke detectors and fire extinguishers maintained; teach basic fire safety plus how and when to call 911; try to avoid cooking burns

* play on soft surfaces and keep an eye out for fall risks

But yeah, I really don't know which long-term effects of environmental exposure to toxins are the ones I should try the hardest to mitigate.

My current belief is that the best long-term thing we can do for the kids is ensure they don't start smoking. The second worst environmental toxin I think I see right now is added sugar; or more generally an unhealthy diet. My read of the data is that there's evidence that unhealthy diet practices (correlated with high dietary added sugar) could, in the long run, lead to an increased risk of obesity, which dramatically increases the long-term risks of top causes of mortality, like heart disease and cancer.

I don't really have a good sense for how "diet and exercise" stacks up against "avoid low levels of arsenic in the spices I'm feeding the kids" but my gut feeling is that it's like 10x-100x more important.

I did like the idea from https://www.nytimes.com/2020/11/23/parenting/home-flame-reta... that the best thing you can do is buy less stuff. If you're worried about exposure to environmental toxins then buy fewer, less diverse things (stuff you use and food you eat) and hope those are good ones.

Another long-term risk I've been particularly interested in mitigating is skin cancers from sun exposure -- I've been trying to be conscientious about putting sunscreen on the kids when the UV index is in the 6+ range and they're outdoors for 20+ min. This is a very long-term risk and it's sobering that it might not materialize while I'm around to see the results.

People who worry about chemicals do worry that some sunscreens might be worse than others (for example the folks at https://www.ewg.org/sunscreen/report/executive-summary/ produced some attractive charts arguing that you should avoid oxybenzone and stick to zinc oxide). I'm not sure the data show that "choice of sunscreen" is the same order of magnitude as risky as "using or not using sunscreen". Still, if you want to limit your risk to extra potential toxins, it's easy enough to pick exactly one formula and stick to it -- so we've been buying only zinc oxide sunscreen for a while, figuring that it's the same thing that's in Desitin and the kids are getting plenty of it. Whether this was wise I don't know (haven't seen any medical recommendations updated to reflect the results of https://today.oregonstate.edu/news/osu-study-after-two-hours...) but it's easy enough to buy less stuff, or buy fewer kinds of stuff, and that gives some peace of mind.

Overall though my hunch is that the "miscellaneous bad chemicals" stuff is long-tail risk versus "safe driving and healthy diet and exercise".