An employer shall ensure that no employee certified by the occupational medicine practitioner to be unfit for work in an area which exposes him or her to lead, returns to work until-
(a) the occupational medicine practitioner certifies in writing that the employee is fit for such work;
(b) the employee's blood lead concentration is less than 50 μg /100 mℓ: Provided that the return blood lead level of 50 μg /100 mℓ may be phased-in by reducing the level from 70 μg /100 mℓ to 65 μg /100 mℓ with effect from 30 June 2002, and then by a further 5 μg /100 mℓ every twelve months thereafter in order to reach 50 μg /100 mℓ by 30 June 2005, as depicted in the Table contained in Annexure D to these Regulations;
(c) the ZPP value in the blood of the employee is less than 6 μg /g haemoglobin; or
(d) the employee's urinary lead concentration is less than 130 μg/ℓ.