18. In any case where—
(a)the dose limits specified in paragraph 9 are being applied by a radiation employer in respect of an employee; and
(b)the Executive is not satisfied that it is impracticable for that employee to be subject to the dose limit specified in paragraph 1 of Part I of this Schedule,
the Executive may require the employer to apply the dose limit specified in paragraph 1 of Part I with effect from such time as the Executive may consider appropriate having regard to the interests of the employee concerned.