Safety assessment of the substance isobutane, for use in food contact materials

Isobutane, CAS No 75-28-5, FCM Substance No 1069, E 943b, foaming agent, polystyrene, safety assessment, food contact materials
First published in the EFSA Journal
12 January 2018
28 November 2017
Scientific Opinion


The substance isobutane is intended to be used as a foaming agent at max 4.5% to produce expanded polystyrene (EPS) to be used for packaging foods, such as fruits, vegetables, meat, fish and cheese, at room temperature or lower. Isobutane is approved in Europe as a food additive (E 943b) to be used quantum satis as a gas propellant only in vegetable oil pan spray (for professional use only) and water-based emulsion spray according to Regulation (EC) No 1333/2008. The purity requirements for the use of isobutane as a food additive are described in Commission Regulation (EU) No 231/2012. The substance is a gas at room temperature. It is a saturated hydrocarbon, obtained with a high level of purity, and is not expected to react under the processing conditions used to make foamed polystyrene materials and articles. Data on migration of isobutane from trays at 20°C for 10 days ranged from 0.2 to 0.4 mg/kg food. Considering the intended applications, estimated exposure is extremely low based on migration data. In the absence of genotoxicity alerts and given the very low toxicity following repeated exposure with no observed adverse effect concentration (NOAEC) of several thousands of mg/m3by inhalation, it was considered that the use of isobutane as a foaming agent, at the expected exposure from food, does not raise a safety concern.

Panel members at the time of adoption

Claudia Bolognesi, Laurence Castle, Kevin Chipman, Jean-Pierre Cravedi, Karl-Heinz Engel, Paul Fowler, Roland Franz, Konrad Grob, Rainer Gürtler, Trine Husøy, Sirpa Kärenlampi, Wim Mennes, Maria Rosaria Milana, Karla Pfaff, Gilles Riviere, Vittorio Silano, Jannavi Srinivasan, Maria de Fátima Tavares Poças, Christina Tlustos, Detlef Wölfle and Holger Zorn.
Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids
fip [at]
EFSA Journal 2018;16(1):5116
Question Number
On request from
Ministerio de Sanidad, Servicios Sociales e Igualdad, Spain