Yup. I know one guy who after inhaling some vapors (not of his own making) in a shop wound up in the hospital. I don't know what various components/chemicals produced them but he spent the better part of 2 weeks recovering just from getting a sniff. His hangar was well vented as well, with the main door open.
He was building a Long-EZ (of which I won't get into my opinions since they're mine and mine alone
)
