First of all, you should look for professional help. If this phobia affects your life, and it sounds like it does, you should try to work on it. For most phobias, there are very good behaviour therapy approaches available which help you dealing with your phobia. Please look for someone therapist!

One practical thing you can do is writing an e-mail to the course instructor asking what kind of chemicals you are about to use within the course and check out how dangerous they are.

First of all, you should look for professional help. If this phobia affects your life, and it sounds like it does, you should try to work on it. For most phobias, there are very good behaviour therapy approaches available which help you dealing with your phobia. Please look for a therapist!

One practical thing you can do is writing an e-mail to the course instructor asking what kind of chemicals you are about to use within the course and check out how dangerous they are.