A proposal in the Florida House of Representatives would limit the  levels of Tetra-hydro-cannabinol, or THC, in smokable medical marijuana at 10 percent. THC is the substance that produces the high in marijuana. Ray Rodrigues, Chairman of the House Health & Human Services Committee, said studies have found that found high levels of THC were not effective in treating pain. Industry insiders say most of the plants grown by the state’s medical marijuana operators range between 15 and 24 percent THC. The bill also includes a provision that would allow veterans to get free medical-marijuana patient identification cards, which currently cost patients and caregivers $75 each year.