23.—(1) Where any accident or other occurrence takes place which is likely to result in a person receiving an effective dose of ionising radiation exceeding 6mSv or an equivalent dose greater than three-tenths of any relevant dose limit, the employer shall—
(a)in the case of a classified person, arrange for a dose assessment to be made by the approved dosimetry service forthwith;
(b)in the case of an employee to whom a dosemeter or other device has been issued in accordance with regulation 12(2), arrange for that dosemeter or device to be examined and for the dose received to be assessed by the approved dosimetry service as soon as possible;
(c)in any other case, arrange for the dose to be assessed by an appropriate means as soon as possible, having regard to the advice of the radiation protection adviser.
(2) In such a case, the employer shall—
(a)take all reasonably practicable steps to inform each person for whom a dose assessment has been made of the result of that assessment; and
(b)keep a record of the assessment or a copy thereof until the person to whom the record relates has or would have attained the age of 75 years but in any event for at least 50 years from the date of the relevant accident.