19.—(1) Subject to paragraph (2), every employer shall monitor the exposure of his employees to asbestos by measurement of asbestos fibres present in the air—
(a)at regular intervals; and
(b)when a change occurs which may affect that exposure.
(2) Paragraph (1) shall not apply where—
(a)the exposure of an employee is not liable to exceed the control limit; or
(b)the employer is able to demonstrate by another method of evaluation that the requirements of regulation 11(1) and (5) have been complied with.
(3) The employer shall keep a suitable record of—
(a)monitoring carried out in accordance with paragraph (1); or
(b)where he decides that monitoring is not required because paragraph 2(b) applies, the reason for that decision.
(4) The record required by paragraph (3), or a suitable summary thereof, shall be kept—
(a)in a case where exposure is such that a health record is required to be kept under regulation 22 for at least 40 years; or
(b)in any other case, for at least 5 years,
from the date of the last entry made in it.
(5) In relation to the record required by paragraph (3), the employer shall—
(a)on reasonable notice being given, allow an employee access to his personal monitoring record;
(b)provide the Executive with copies of such monitoring records as the Executive may require; and
(c)if he ceases to trade, notify the Executive forthwith in writing and make available to the Executive all monitoring records kept by him.