food items depending on variables such as pH of the food stuff. The toxicity considerations of a specific material may include the carcinogenity of the substance. The regulations governing these aspects may vary in different nations. Note that the "food safe" symbol doesn't guarantee food safety under all conditions. The composition of materials contacting foodstuffs aren't the only factor controlling carcinogen migration into foodstuffs; there are other factors that can have a significant role in food safety. Examples include: the temperature of food products, the fat content of the food products and total time of contact with a surface. The safety of foam food containers is currently debated and is a good example of all three of these factors at play. Polystyrene may melt when in contact with hot or fatty foods and may pose a safety risk. In the United States, materials in contact with food may not contain more than 1% residual styrene monomers by weight (0.5% for fatty foods). Bisphenol A Diglycidyl ether-based epoxy coatings are extensively used for coating the inside of cans which come into contact with food and are thus food contact materials. The materials and analogues and conjugates have been extensively tested for and analytical methods developed. Legislation European Union The framework Regulation (EC) No. 1935/2004 applies to all food contact materials. Article 3 contains general safety requirements such as not endanger human health, no unacceptable change in the composition and no deterioration of the organoleptic characteristics. Article 4 set out special requirements for active and intelligent materials. Article 5 specifies measures for groups of materials that may be detailed in separate regulations of directives. Member States may maintain or adopt national provisions (Article 6). Articles 7–14 and 22–23 deal with the requirements and application for authorisation of a substance, modification of authorisation, the role of the European Food Safety Authority, the Member States and the Community. Article 15 is about labeling of food contact materials not yet in contact with food. Article 16 requires a declaration of compliance and appropriate documentation that demonstrate compliance. Articles 17–21 deal with traceability, safeguard measures, public access of applications, confidentiality, and data sharing. Article 24 sets out the inspection and control measures. Specific measures for materials and articles such as ceramics, regenerated cellulose, plastics, gaskets and active and intelligent materials, and substances such as vinyl chloride, N-nitrosamines and N-nitrostable substances in rubber, and epoxy derivatives, exist.