142. (1) Subject to paragraphs (3) and (4), the Authority, by a certificate in writing, may exempt any person or class of persons from Regulation 139 in duly justified circumstances in respect of whole-body vibration only in the case of sea and air transport, where the latest technical advances and the specific characteristics of the place of work do not permit compliance with the exposure limit value despite the technical and organisational measures taken.

(2) Subject to paragraphs (3) and (4), the Authority, by a certificate in writing, may exempt any person or class of persons from Regulation 139 where the exposure of an employee to mechanical vibration is usually below the exposure action value but varies markedly from time to time and may occasionally exceed the exposure limit value, provided that—

(a) any exposure to mechanical vibration averaged over 40 hours in any one week is less than the exposure limit value, and

(b) there is evidence to show that the risk from the actual pattern of exposure is less than the corresponding risk from constant exposure at the exposure limit value.

(3) The Authority shall not grant any exemptions under this Regulation unless—

(a) the Authority consults the employers and the employees concerned or their representatives, or both,

(b) it applies conditions to any such exemption, taking into account the special circumstances, to ensure that the resulting risks are reduced to a minimum, and

(c) appropriate health surveillance is available to the employees concerned.

(4) Any exemption granted by the Authority under this Regulation shall be—

(a) reviewed by the Authority at least once every 4 years, and

(b) revoked by the Authority, by a certificate in writing, at any time as soon as the justifying circumstances no longer obtain.