A Swiss health organization (Blue Cross) had IQOS polymer filters tested when heated to 100°C and found that it emits isocyanate.

Media

• English: swissinfo
• German: Nau
• German: Tagesanzeiger
• German: 20 minutes
• German: bluewin
• German: Blick
• French: RTN

Isocyanate

This chemical is extremely toxic in even very low concentrations and will cause severe health damage in prolonged exposure. 3 months will see you severely sick, a year will see you dead.

It is the same chemical that's responsible for the Bhopal disaster where 8000 died within weeks and the impact to date is about 16'000 dead and 558'000 injured. Among the ongoing effects are fatty degeneration of the liver, stillbirths, fetus deformations and many others.

IQOS

These "heat not burn" electronic cigarettes consist of a heater "blade" that's shoved into a stick of PG-soaked tobacco and then the whole thing is heated to 350°C. The heating element is approximately 2cm long, the tobacco stick about 5cm long and then comes the polymer filter (allegedly made from PLA).

Phillip Morris denies that isocyanate is emitted in use, but admits that the filter contains isocyanate.

The Blue Cross contests that the filters partially melt during use, bringing them to temperatures sufficient to release isocyanate, but admits they didn't test isocyanate emission during actual use.

Previous research (reported by the guardian) has shown that people speed up their puff rate to inhale more nicotine. As a result the blade and heating chamber overheat, tobacco pyrolizes and plastics partially melt, leading to a release of formaldehyde and cyanohydrin.

Phillip Morris has denied the emission of formaldehyde and cyanohydrin and claimed the polymer filters are "made of starch" (i.e. PLA) and can't release the toxic substances.

My thoughts

To my knowledge PLA does not release isocyanate when heated (it's the same stuff most people use for 3D-printing). However PLA is often combined with other plastics to improve its properties. The worst offender of emitting isocyanate when heated is polyurethane, which is not usually combined with PLA (not for 3D printing anyway, and should certainly not be used in food products). It is possible that Phillip Moris (since they admit the polymer filter contains isocyanate) has combined the PLA with another not commonly used plastic in food products/3D printing that does release isocyanate (that would be spectacularly stupid and irresponsible).

It's why I have speculated in this post Phillip Morris is trying to "tab clear" vaping, by making an electronic cigarette that's so bad, and may draw the ire of health organizations, it's intended to kill vaping by association.