Who caused the problem with Formaldehyde

Formaldehyde is a highly reactive molecule that can be directly irritating to tissues with which it comes into contact. Human and animal studies indicate that formaldehyde, at certain exposure levels, can be irritating to the upper respiratory tract and eyes with inhalation exposure, to the skin with dermal exposure, and to the gastrointestinal tract with oral exposure. Formaldehyde-induced noncancer and cancer effects appear to occur only at portals-of-entry (i.e., upper respiratory tract, gastrointestinal tract, and skin).

the effect of the ming leaders banning ships with more than two masts was that there was no further construction of ships masts, because there was a surplus. ming emperors disallowed foreign exploration