Avoidable accident: Drainage Services Department Assistant Director Chow Man-tat explains the investigation findings.

The Drainage Services Department will take disciplinary action against contractor Shun Yuen Construction, which was found to have committed serious mistakes leading to the death of two workers in a Sha Tin manhole on August 1.

Announcing the department's investigation findings today, Assistant Director of Drainage Services Chow Man-tat said the firm sub-let the works without permission. There was a second layer of subcontractor instead of only one as reported by the company in the Subcontractor Management Plan.

"The main contractor's blatant violation of contract provisions and the associated safety regulations has brought about the fatal incident. This is totally unacceptable," he said.

It conducted works outside the intended site area without permission, and failed to take necessary precautions. Mr Chow said the tragedy could have been avoided.