Emergencies

   18. Possible defence in cases of unforeseen emergencies---(1) Any
 person who is prosecuted under section 338 for any offence arising from
 a contravention of any of sections 9, 11, 12, 13, 14, and 15 may raise
 any defence that is referred to in section 341.

   (2) No person may be prosecuted for acting in accordance with section
 330 (which relates to certain activities undertaken in an emergency).