Andy Dick's Crack Smoking Helped Him Avoid Fentanyl Death, DEA Sources Say

Andy Dick has gotten lucky if he mainly uses crack cocaine to get high, our law enforcement sources say ... because fentanyl isn't generally mixed in with the drug.

Two current federal Drug Enforcement Administration officials tell TMZ ... mixing fentanyl with crack's a fool's errand. The substance burns off with heat -- so putting it in the drug wouldn't produce the desired effect.

The chemical structure of fentanyl breaks down once someone lights up the rocks ... and it loses its potency. We're told the drug will still have some effect, but it simply won't be as strong -- and it certainly won't have a lethal effect on a person.

Fentanyl is mostly snorted or injected ... making drugs like cocaine or heroin more likely to contain some of the killer powder. Despite his overdose this week, Dick has been arrested for cocaine possession in the past.

In a recent interview with TMZ, Andy admitted to only smoking crack on a Hollywood street Tuesday ... but he more than likely also consumed an opioid, because he was revived with a Narcan shot. William Bodner, the former head of L.A.'s DEA Office, tells us Narcan only reverses the effects of opioid overdoses, such as fentanyl or heroin, not crack cocaine.

Bodner says crack is a stimulant that would produce a stroke or a heart attack in people who smoke too much of it, sending them to the hospital. That's not what happened to Andy -- and Bodner says the big question is whether Andy knew what he was smoking, was tricked into taking another drug ... or simply didn't care what he was ingesting.

Worth noting ... we've also talked to sources who say Andy's far more into alcohol than drugs -- another reason Dick wouldn't run into fentanyl all that often.

We broke the story ... Andy suffered an apparent overdose earlier this week, with video showing the slumped-over star unable to keep himself upright while a bystander administered Narcan.