The Financial Post reports in its Thursday edition that Essential Energy Services chief executive officer Garnet Amundson says once recreational pot becomes legal it will get harder to find the workers to handle volatile chemicals, operate heavy equipment, and work with high-pressure pipes and valves. A Bloomberg dispatch to the Post reports that Mr. Amundson only hires people who pass a drug test. He is not the only employer who is worried. The problem is that the active ingredients in marijuana can remain in a person's bloodstream for weeks, long after the high is gone. Currently, there is no way to tell whether a candidate indulged in pot at home over the weekend or in the car on the way to work. If legal weed boosts casual pot usage, there is a risk that fewer applicants will be clean enough to hire. The prospect of more failed drug tests is a big concern for an energy industry that is expanding and needs more workers. Companies already are having a hard time hiring enough qualified people to perform jobs that are physically demanding and require long stretches in remote locations. Legal weed would create a new dilemma for employers that long ago adopted drug and alcohol testing for high-risk jobs.