Last year I started oil painting, which means (in part) that I use paint thinner for working with and/or cleaning brushes. I recently became concerned about my exposure to the vapor from the paint thinner I use, so I requested a toxicology report from the manufacturer. In the document it specifies that the summated $\mathrm{LC}_{50}$ for the product is 21400 mg$\cdot$ m$^{-3}$.
My (basic) understanding of this is that 50% of test subjects will die with a single exposure at the above level; however, I've really no idea how that translates to "real life" and wonder if someone can shed some light on it.
I'm painting in a reasonably small room (around 3 m x 5 m) with windows open, so I'm essentially trying to determine if this is safe or not, or whether I should be using breathing apparatus and/or move to a different room.
This is a link to the whole document which I received from the manufacturer which contains the substance and other information.