An employer must establish and maintain a documented system of medical surveillance of employees, which is overseen by an occupational health practitioner, if-
(a) the results of the HBA risk assessment contemplated in regulation 6 indicate that an employee is at risk of exposure to HBAs;
(b) the exposure of the employee to the HBA is hazardous to his or her health and is such that-
(i) an identifiable disease or adverse effect to his or her health may be related to the exposure;
(ii) there is a reasonable likelihood that the disease or effect may occur under the particular conditions of his or her work; and
(iii) there are techniques such as preclinical biomarkers, where appropriate, for detecting sensitisation to allergens or an inflammatory response associated with exposure to diagnose indications of the disease or the effect as far as is reasonably practicable; or
(c) an occupational health practitioner recommends that the relevant employee should be under medical surveillance, in which case the employer may call upon an occupational health practitioner to confirm the appropriateness of such recommendation.