To date the EHSU plays a key role in ensuring that the MOWT conforms primarily to two (2) major types of legislation:
 * Environmental Management Act was enacted in 2000 and its subsidiary legislation, the Certificate of Environmental Clearance Rules, was enacted in 2001. The latter legislation mandated the then Ministry of Works and Transport to procure the Certificate of Environmental Clearance (CEC) for all projects which fall under the Designated Activities Order, 2001 and conduct Environmental Impact Assessments for all major projects where environmental impacts were deemed to be significant.
 * In 2006, the OSHA was proclaimed and the MOWT had a responsibility to oversee the health, safety and welfare of all its employees.  As a result, in 2009, the restructuring of the Environmental Unit to the Environmental, Health and Safety Unit was done to facilitate compliance with the OSHA.