In 1980, he formed S.K. Hart Engineering, a consulting services company for the newly sensitive and growing environmental protection industry.  Recognizing the need for a proper repository for the disposal of hazardous wastes created as a byproduct of the manufacturing and other industrial processes, Khosrow Semnani was responsible for the design, permitting, and development of the first hazardous waste disposal facility in the State of Utah–Grassy Mountain.  Khosrow Semnani later sold his interest in the facility to an Oklahoma based company and the facility continues to operate under subsequent new ownership.

From 1984 to 1987, Khosrow Semnani was involved in residential and commercial land development and other real estate activities in Wendover and the Salt Lake Valley.  In 1988, recognizing another environmental need, Khosrow Semnani designed, licensed, and developed, a first of its kind in the US, commercial low-level nuclear waste disposal facility; Envirocare of Utah, Inc.  Under his leadership, Envirocare grew to become the largest low-level nuclear waste disposal facility in the United States, disposing between 500,000 and 600,000 cubic yards annually.

After 17 years as the owner-operator, Khosrow Semnani sold Envirocare in 2005 to a consortium of private investment firms.

Khosrow Semnani’s current business plans involve international opportunities, farming ventures in Africa, expanded management of his real estate holdings and investments in energy and renewable resources.