Organic compounds in the form of salts and esters of carbamic acid, often referred to as urethanes. Carbamates have been used since the 1950s, mainly as fungicides, herbicides and insecticides in agriculture. Some carbamates were also used as sleeping pills in the past. A natural substance is ethyl carbamate, which is produced during fermentation and is therefore also present in small quantities in wine. It was included in the list of substances suspected of being carcinogenic at the end of the 1980s following animal experiments. In most cases, however, the quantities of carbamates contained in wine are far below the maximum limit of 8 mg/l. The quantities are highest in sweet wines with a high alcohol content which have been heated during the production process, such as Madeira, and in spirits. A higher proportion may also be caused by excessive fertilisation with nitrogen.