The hazard symbol for flammable/highly flammable substances according to directive 67/548/EWG by the European Chemicals Bureau. This version works out better than Image:Hazard F.svg for use as small thumbnail (20-50px), no black border.
Image:Hazard F.svg, original from Clipart Gallery on sodipodi.com, http://www.sodipodi.com/index.php3?section=clipart/symbols
User:NielsF