The journal Meat Science provides a thorough overview of the content of various chemical substances and pollutants in meat and meat products. These include heavy metals (e.g. lead and cadmium) and dangerous industrial chemicals with the potential to seriously damage human health. The authors also looked into the content of cancer causing substances in smoked meat products and it was suggested that the EU limit is too high and should be significantly lowered. As for the nitrogen salt used for reddening and preserving some meat and meat products, it was confirmed that resulting compounds found in meat are strong carcinogens. The review also lists veterinary drug residues in meat including banned drugs.
Andrée et al., 2010. Chemical safety of meat and meat products. Meat Science. 86 (1) 38-48.