I hear its the new meth, which was the new heroin, which was the new crack, which was the new cocaine, which was the new heroin...
Also, I wonder how safe this new mj-ish stuff is relative to old-school mj?
Much less safe. Old school mj is pretty safe unless it is laced or otherwise combined/contaminated with other agents. Roughly double as risky as tobacco, give or take. In other words, virtually no short term risk except for asthmatics/allergies but long term health risks. You'd be extremely hard pressed to find an example of THC lethal overdose, if it has EVER happened.
New stuff is ... Extremely variable. Some of it is pretty friggin dangerous, others mildly so. From what I understand, it is wildly variable in terms of risk and effects. That is actually the largest risk. You have little to no knowledge of reactions, because of the complete lack of QC and difficulty in effective testing.
vaskidmark is point on. Hospitals very much need a secondary tox screen for these. It will unfortunately be significantly more complicated compared to garden variety opiates, THC, amphetamines, ethanol and barbiturates.