Authors are right. While it’s under the “safe” measure, it should be concerning that people have been using such things that degrade for so long. It has contributed to some problems for people, even if the risk is lower than a maximum.

But if you sort it with all the other things in the world, I guess it’s just something to try and avoid but not necessarily worry about the past.

The EPA’s safe level is 7,000 ng—per kilogram of body weight—per day, and the authors used 60 kg as the adult weight (about 132 pounds) for their estimate. So, the safe EPA limit would be 7,000 multiplied by 60, yielding 420,000 ng per day. That’s 12 times more than the estimated exposure of 34,700 ng per day.