How toxic certain materials and chemicals are could be dependent on the extent of exposure, and how susceptible an individual is. As for toxic woods, this site
has a list.
Most composite board sheet stock uses a urea-formaldehyde glue in it's process. Some manufacturers have substituted glue types. For specific brands and types, look at the MSDS
(Material Safety Data Sheet) specifications for the particular item.
As for chemical vapor inhalation, many common shop chemicals are very toxic, such as lacquer thinner, mineral spirits, acetone, lacquer paint, some urethanes, solvent based contact cement and others. This hazard is extended to virtually any area that can be affected such as the ear openings, eyes, nose, and other orifices that I won't mention.
For the toxic or hazardous chemicals, direct contact with the skin is also a source of ingestion. What can the results produce? Many ailments can be attributed to absorbed chemicals. I for one have been a victim of nerve damage in the fingers and hands, bladder cancer, respiratory problems, and some loss of smell sensitivity. As for brain damage...the jury is still out on that one.
My exposure can be considered extreme, being a daily event for 38 years. When very little data was available on these safety issues, there was a natural aversion to properly equip a shop with an effective dust system, respirators for non-spraying procedures, and the use of gloves. Shop owners then had an attitude like "real men don't need that stuff". Well, contrary to that type of thinking, I found out they definitely do.