[bri3d]

Additives labeled P-21-0152 and P-21-0158 are the specific substances with the extreme cancer risk as modeled, I think?

These appear to be complex hydrocarbon byproducts of plastic, so it's extremely difficult to model what they are or their actual behavior. The EPA basically use a combination of analog substances and "stuff they think might be similar" and then add the risks together to make a score.

The EPA analysis is much more useful than any of these articles. I don't think the analysis itself supports the breathless claims in the news article. I do ultimately agree that this feels odd, though: while I don't think any of these materials are actually that likely to cause cancer, it seems a bit strange to be approving fuel additives with this much uncertainty in analysis. But, I don't work in hydrocarbons so maybe this is normal.

https://www.documentcloud.org/documents/23863526-epa-hq-oppt...