The secretary of health and environment may organize the department of health and environment in the manner he or she deems most efficient, so long as the same is not in conflict with law. The division heads and staff assistants shall perform such duties and exercise such powers as are prescribed by law and such other duties as the secretary of health and environment may prescribe. Such division heads shall act for, and exercise the powers of the secretary of health and environment to the extent authority to do so is delegated by the secretary of health and environment. The secretary of health and environment shall delegate to the director of the division of environment, created by this act, the powers, duties and functions vested in the division of environmental health, director of the division of environmental health and engineer of the state board of health prior to the effective date of this act, except as is herein otherwise provided. Personnel of each division shall perform such duties and exercise such powers as the head of the division may prescribe and such duties and powers as are prescribed by law. Personnel of each division shall act for, and exercise the powers of their division head to the extent authority to do so is delegated by the division head.