Unfortunately there is little scientifically factual information available on safety topics.
Some information from my research is posted on this this thread below (starting with post #12 from GeneticBrew "One benefit to 3 big stainless kettles is food grade material"). Also on this thread the links to the toxicologist interviewed on Basic Brewing podcasts:
Many brewers’ personal efforts reflect a commitment to integrity of the brewing process; that is both safe and produces a beer of purity and tastiness.
Historically, the German purity laws were an early benchmark towards a mindset of making the ingredients safe and a commitment to integrity of process.
The home brewer should have access to appropriate information. With this, the home-brewer can make an informed decision as to the level of safety and integrity of process to incorporate into their own beer.
It is unfortunate that such information is not more widely available.