Saltire detected the symbol, which often appears with balls in the quadrants formed by the arms of the chi-cross, in standards that appear on the coins of Persepolis. She suggested that early Christians endorsed its solar symbolism as appropriate to Christ. She also wrote: "although it cannot be proved, ... in the white saltire of St. Andrew we still have a reminiscence of the old standard of the Persepolitan kingdom". In the old European Union standard, a black saltire set in an orange square is the hazard symbol for irritants (Xi) or harmful chemicals (Xn). It indicates a hazard less severe
Hazard symbol understood (the same symbol can be recognized as having the same meaning to speakers of different languages). On roadside warning signs, an exclamation mark is often used to draw attention to a generic warning of danger, hazards, and the unexpected. In Europe, this type of sign is used if there are no more-specific signs to denote a particular hazard. When used for traffic signs, it is accompanied by a supplementary sign describing the hazard, usually mounted under the exclamation mark. This symbol has also been more widely adopted for generic use in many other contexts not associated with road traffic.