How do you know if Marijuana has PCP in it?

I have a heart murmur and if i'm going to have some weed, i don't want any thing else in it (except tobacco). I heard sometimes weed has some PCP sprinkled on it.

How do i tell if i want to smoke weed, that it is safe?

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Answer:
it only has pcp if it's laced

nearly any kind you find won't have it

only stupid people have weed laced with pcp
so assume not

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Answer:
You won't know if it has PCP in it or not until you wake up in the hospital or you don't wake up at all. For your sake, assume it all has PCP in it and leave it alone! Believe me, you’re not missing a thing.
Go find some other thing to do that you think is “cool” that won't harm you or others.

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Answer:
Grow your own, then you know it's safe.