11. (1) The employer carrying on an industry subject to the authority of this Act shall be considered to be the immediate employer of any worker of a contractor or sub-contractor executing any work for such industry:
(a) until such contractor or sub-contractor shall, in respect of such work, have made the declarations required and is assessed as an employer in an industry designated by regulation; or,
(b) in cases where such contractor or sub-contractor is individually liable for payment of benefit, until the Commission finds and declares that the solvency of such contractor or sub-contractor is sufficient protection for his workers and sufficient security for the benefits provided for by this Act.
(2) Where the employer has made payment, under subsection 1, of assessment or benefit, he is entitled to reimbursement from the contractor or sub-contractor to such extent as the Commission may determine.
(3) Where a person, referred to in this subsection and in subsection 4 as the “principal”, carrying on an industry subject to this Act, contracts with any other person herein called: “the contractor or sub-contractor”, for the execution by such contractor or a sub-contractor of the whole or any part of any work for the principal, it is the duty of the principal to see that any sum which the contractor or sub-contractor is liable to contribute to the accident fund is paid; and if any such principal fails to do so, he is severally liable to pay it to the Commission, and the Commission has the like powers and rights to compel the principal to pay, as it possesses for the collection of an assessment.
(4) Where the principal is liable to make payment to the Commission under subsection 3 of this section, he shall be entitled to be indemnified by any person liable therefor and may withhold out of any indebtedness to such person a sufficient amount to do so.