If there is any truth to those numbers you may rest assured it probably derives from the use of "ditchweed," i.e., immature plant material which has been spiked by a bootlegger with some substance (liquified heroin, etc.) to produce a euphoric effect and boost the price. Improperly done this can be toxic.
Also, it is not uncommon for "ditchweed" to be sprayed with toxic and carcinogenic pesticides and growth-inducing hormones (e.g., gybirillic acid), some of which can be very harmful. This problem is analogous to the "bathtub gin" produced by bootleggers during alcohol prohibition which resulted in many deaths as well as emergency room visits.
Another possibility is ignorantly attempting to make edible marijuana products, like brownies, which is increasingly common and can make one sick. Some people think the way to do this is just grind up some leaf and bud and mix it in with cake batter, which can seriously clog the intentines. There is a specific process involved in extracting THC oil to make "pot butter," and it calls for experience and some level of expertise.
Please note that all of the above problems are consequences of prohibition, which facilitates public ignorance.
If you would like to learn the truth about marijuana and no longer be receptive to the kind of
Reefer Madness propaganda which clearly has misled you, Jack Herer has made most of the text of his interesting, well-documented book,
The Emperor Wears No Clothes, available on-line -- and FREE! Just go here:
The Emperor Wears No Clothes by Jack Herer - Read It Here