OKLAHOMA CITY (AP) — Oklahoma's exploding medical marijuana industry has opened doors for security entrepreneurs.

Duncan-based Stronghold Protection Group and Oklahoma City-based Hendrickson Investigation & Protection LLC are two companies providing armed guards and specialized transportation to protect the cash.

Stronghold co-owner Clint Gann told The Oklahoman that that he used his trucking and transportation background to work with partner Brendon Davis, who has security experience. Gann said the two realized the need for security because of the potential danger of transporting cash as they...