Indiana residents who smoke marijuana legally in states that allow it could face prosecution or firing once they're home even if they aren't intoxicated. Legal experts say having just a trace of marijuana in one's system can lead to a conviction for operating while intoxicated or dismissal from a job under Indiana laws. Nearly two dozen states have legalized marijuana use in some form. Alaska, Colorado, Oregon and Washington, along with the District of Columbia, allow recreational use of the drug. At least one attorney says the issue is “legally concerning” for people who are trying to stay within the law by smoking marijuana only where it's legal to do so.