From what I know, Tin lined cooper and Stainless Steel (SS) are the safest and most practical to use. Although SS contains Nickel and Chromium, the amount released at cooking temperature is negligible to the human body.
I own both type of cookware and tin is easier to clean.
I would not recomment using Non-Stick coated cookware since these materials release gases/compounds.
"Tell me what you eat, and I will tell you what you are" Anthelme Brillat-Savarin