# The Explosives in Harbour Areas Regulations (Northern Ireland) 1995, Paragraph 2


Each hazard warning sign shall be in the form of a square set with its sides at an angle of 45° to the vertical and the length of the sides shall be not less than 100 millimetres, except that, in the case of receptacles that are of such dimensions that they can only bear smaller signs, the sign should be as large as is reasonably practicable.

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Source: https://www.legislation.gov.uk/nisr/1995/87/schedule/1/paragraph/2 (the official version)
Page: https://openlegislation.uk/explosives-in-harbour-areas-regulations-northern-ireland-1995/schedule-1/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.