(2) After reaching a decision in terms of subsection (1), the head of the public body shall give notice, in writing, of his decision to both the applicant and the third party. (3) If the head of the public body decides to give access to the record or to part of the record, the notice shall state that the applicant will be given access to the record within twenty days after the date the notice is given, unless the third party requests a review in terms of Part X. 28 Information to be disclosed if in the public interest (1) The head of a public body shall have a duty to disclose to— (a) an applicant; or (b) members of the public or interested or affected persons, whether or not a request has been made; information concerning— (i) the risk of significant harm to the health or safety of members of the public; or (ii) the risk of significant harm to the environment; or (iii) any matter that threatens national security; or (iv) any matter that is in the interest of public order; or (v) any matter that assists in the prevention, detection or suppression of crime; or (vi) any threat to public security or public order: Provided that information concerning any threat to public security or public order shall only be disclosed to the relevant law enforcement authorities. (2) Before disclosing any information in terms of subsection (1), the head of a public body shall, if possible, notify any third party to whom the information relates or directly affects and the Commission. (3) If it is not reasonably possible to comply with subsection (2), the head of the public body shall mail a notice of disclosure in the prescribed form to the last known address of the third party and to the Commission. PART V COLLECTION, PROTECTION AND RETENTION OF PERSONAL INFORMATION BY PUBLIC BODIES 29 Purposes for which personal information may be collected A public body may only collect personal information if— (a) the collection of that information is expressly authorized in terms of an enactment; (b) the information is to be collected for the purposes of national security, public order and law enforcement; or (c) the information is to be collected for the purposes of public health; or (d) the information relates directly to and is necessary for an operating programme, function or activity of the public body; (e) the information will be used to formulate public policy. 18