I can't really address your concern directly, Woolly Bugger. It's been a few years since I was involved with this sort of thing. But my recollection is that, since you did not disclose your disability when you were hired, the employer is not obligated to provide reasonable accommodation. If you are concerned about the possibility of losing your job, as a result of your bp diagnosis, you may want to check out your rights under ADA prior to disclosing. If there is a legal advocacy or disability rights organization in your area, that might be a good place to contact.