Science had evolved massively in 50 years. We used to put lead in gasoline too.

We've known lead was harmful for nearly 2,000 years though [1]. Compare that timeline to compounds created, widely used, and then discovered to be harmful in the past 50 years.

I am not advocating for lead or copper soldered water pipes, but I am conservatively skeptical about PVC being totally safe for the same timeline existing lead pipes have been in use. In July the EPA proposed raising the priority rating of vinyl chloride on its toxic substances list. It doesn't seem implausible to me that in 50 years we'll be taking about PVC pipes the same way were talking about lead pipes today.

I am not claiming that PVC water pipes are dangerous just that I am skeptical there is enough historical data to claim they are totally risk free. I am not a scientist or expert on this subject

1.https://penelope.uchicago.edu/encyclopaedia_romana/wine/lead...

Edit: added source

People knew lead was harmful in large quantities, sure, but the science around just how bad lead is and how little can cause damage I would say was not known.

Regarding PVC: It already is not used in almost any new construction for water supply lines, at least in the US. It's used for drains, but the leeching concern isn't really an issue for drain pipes. No water pressure, and no continuous immersion typically. Issues about BPA/vinyl compounds are

As per PEX, I can't say for certain that it's 100% risk free, but overall there is increased scrutiny on drinking water and contaminates and PEX right now seems to be the best choice.