Environmental sources of lower levels of nickel include tobacco, dental or orthopaedic implants, stainless steel kitchen utensils and inexpensive jewellery. Tobacco smoking is another, not negligible, source of non occupational exposures to nickel. It has been estimated that each cigarette contains nickel in a quantity of 1.1 to 3.1 μg and that about 10-20% of the nickel inhaled is present in the gaseous phase. According to some authors, nickel in tobacco smoke may be present in the form of nickel carbonyl, a form which is extremely hazardous to human health. pipe tobacco, cigarettes and other types of tobacco products do not greatly differ one from another in the content of nickel