There's been a lot of chatter in various online venues concerning OSHA's recent "electronic reporting rule" and anti-retaliation language therein related to post-incident/accident substance testing in the workplace. The details straight from the horse's mouth are available here (https://www.osha.gov/recordkeeping/finalrule/finalrule_faq.html), so I won't bore you with the specifics. I will, however, offer a few words of caution...
The tenor of many articles and comments is that OSHA is effectively putting an end to "automatic" across-the-board post-incident/accident testing. I don't think anybody (including OSHA) really believes that things are that clear-cut. Put simply, OSHA's initial position (which will likely evolve between now and November 1st -- OSHA's delayed date for enforcing the anti-retaliation portion of the rule) is that substance testing can have a chilling effect on injury reporting. Given this, automatically testing employees after all injuries could cause habitual drug users/abusers to avoid reporting an injury to avoid testing and possible discipline (the retaliation part).
Taking a cautious and thoughtful approach here is the best advice. Your injury reporting, substance testing, progressive discipline, and employee assistance programs should be reviewed holistically to assess compliance risk. This will allow you to determine -- in light of the totality of your programs -- whether you're sufficiently encouraging injury reporting while still protecting your interest in maintaining a safe, drug-free workplace.
Last words: When you do conduct your review, make sure you assemble a cross-functional team that includes operations, EH&S, HR, and, of course, your friendly neighborhood OSH attorney.