Specifically, formaldehyde-based glues.

"Most manufactured wood building materials contain one of these two types of formaldehyde-based glues:

* Phenol-formaldehyde (PF)

* Urea-formaldehyde (UF).

Its water resistant properties make phenol-formaldehyde glue more effective for production of exterior wood materials. Urea-formaldehyde glue, cheaper and less tolerant of excessive moisture, is most often used for interior materials including wall paneling, flooring and cabinetry. "

More details here: http://www.healthyhouseinstitute.com/hhip-780-Formaldehyde-B...

Formaldehyde. It’s actually pretty unenvironmental. Because it uses formaldehyde and other chemicals, you can’t sand or refinish bamboo, and the dust is extremely hazardous.

Yeah, I was surprised too. They talk about a lot about the bamboo part but not at all about the glue part. And the glue part is certainly the most problematic one. Also, but that may be too much interpretation, you'll notice that the dirtier the place/the job; the more you see women on the pictures.