Headache is not an adverse reaction to being exposed to this. It causes problems within the resperatory system, breathing problems, etc. Once you remove yourself from the toxic vapor of this, your symptoms go away. Maybe there is something else in your work environment causing your headache? It sounds like you are working with things that could be potentially dangerous. If your headaches don't go away when you've been away from your work environment, then it probably isn't work related. Your doctor has ruled out basic problems, but what about your eyes? You may need glasses or a change in your current prescription, this causes constant headaches. There are so many causes of headache, even stress. If they are severe, or appear to be getting worse, I would see a neurologist. Hope this helps....