I would reconsider, if possible, the entire practice by switching to one-shot solutions (you breath much less chemicals that way, I do believe), laboratory pipettes or syringes to mix chemicals, ventilation of the darkroom. When I mix my chemicals I never happen to touch them and I now forget about apron, gloves etc. as I find that attention in manipulation is key. Have space at your disposition, always make gentle, slow movements. Never "park" a flask near the edge of the furniture. Immediately close the flask after dilution (before agitation) etc.
Breathing "fumes" is probably my greatest intake of chemical rubbish but generally speaking an open window will dilute vapours from my already diluted (one-shot) baths. I suppose the worst case is when developing prints, by staying in fact with your nose just over the chemicals. That I think would certainly require a thought-about ventilation.
Chemicals used for colour developing are not so poisonous that single events might give problems (wounds apart). Just wash immediately, and don't drink. It's the continuous small contact (fumes, or drops from a hasty preparation) that is probably to be considered mostly.
And do label any bottle with the content.