Public support for marijuana legalization is at a record high in the United States, but not everybody is embracing reform.

Certain industries have a financial interest in keeping weed illegal — private prisons, law enforcement, and Big Pharma, for example— but there's another opponent to legalization that most people don't think about: the drug-testing industry.

Against mounting evidence that drug testing is not cost effective, and that it unfairly targets marijuana users, the industry remains steadfast in its opposition to legalization. The reason? The industry has a lot at stake. There are those who argue it has a conflict of interest in opposing legalization efforts and is ignoring the facts to justify its fat revenues. More on this later.

In an effort to understand how and why many members of the drug-testing industry appear to be working against the marijuana legalization movement, ATTN: looked at federal...