C&EN: Thickening agents other than vitamin E acetate causing vaping injuries?

Great article from Chemical and Engineering News (by Britt Erickson) on the chemistry angle around the mysterious vaping illnesses, with this unusual tidbit about agents other than vitamin E acetate that may be responsible for the problem: 

Thickening agents are common in illicit THC cartridges, but they are rarely added to legal products where testing for potency is required, says Jeffrey Raber, cofounder and CEO of the Werc Shop, a California-based cannabis contract manufacturing and testing firm. 

“THC concentrates are known to be thick and viscous when they are high potency,” Raber says. So when street dealers dilute illicit products with various agents to maximize profits, those products are typically less viscous. Consumers can visually detect the viscosity of the product by turning the cartridge upside down. If a bubble goes from the top to the bottom quickly, it usually means that the product has been cut with something, Raber says. Dealers mask that visual test by adding a thickening agent, so the bubble doesn’t move from the top to bottom as fast, and consumers think they are getting a high-potency product. 

The illicit cannabis market “is out of control and concerning,” even in states like California where recreational cannabis is legal, Raber says. In California, the cannabis black market is estimated to be 3 to 4 times the size of the legal cannabis industry, he notes. 

One source of the black market problem is that California requires testing of final finished cannabis products, Wise says. If a product fails the test, more often than not, it doesn’t get thrown away. Instead, it enters California’s black market and is then distributed to states where cannabis is illegal, she says.

(Out-of-spec product being reworked for sale? Say it isn't so!)

In a similar news, I found the Mayo Clinic study (covered here by the New York Times) to be interesting, since they did not visually detect signs of lipoic pneumonia, as would be expected if it was vitamin E acetate causing the problem. Rather, the physicians explained it this way:

“All 17 of our cases show a pattern of injury in the lung that looks like a toxic chemical exposure, a toxic chemical fume exposure, or a chemical burn injury,” said Dr. Brandon T. Larsen, a surgical pathologist at the Mayo Clinic in Scottsdale, Ariz. “To be honest, they look like the kind of change you would expect to see in an unfortunate worker in an industrial accident where a big barrel of toxic chemicals spills, and that person is exposed to toxic fumes and there is a chemical burn in the airways.” 

The injuries also look like those seen in people exposed to poisons like mustard gas, a chemical weapon used in World War I, he said.

I find Dr. Larsen's speculation a little confusing, i.e. do pathologists have visual markers for the various types of chemical injuries to the lungs? (They must have, right? I mean, do acidic burns look different than basic (say, ammonia burns), etc., etc?) There can't be just one visual presentation of lung tissue damage from chemicals, can there?

I confess to be very confused as to what exactly is causing the vaping illnesses, and I would really like chemists to get involved to determine what exactly the bad actor (or actors) is/are.