I had a slushie order, and we were out of water. There was a bottle of clear liquid, which I mistook as water. I put in around 3 ounces. Later, My boss informed me that the clear liquid under the water can was not back-up water, but BLEACH. The problem was that they informed me AFTER I had already served the customer! Can either I or the restaurant get sued for this? ( I do not know what is the percentage of concentration.)
Depending on the bleach, you could have just killed the customer, so why in hell are you worried about being sued (to which the answer is a solid “yes”, by the way)? Most bleaches are a horrific poison for which there is little recourse once swallowed - it can easily result in death or permanent life altering injuries.
Being arrested for manslaughter or assault is a real likelihood here, both yourself and your manager. Get legal advice, now.