>> Never again and never to the same child again.
>
>Add within 5 days.

As in the eyes [no pun intended...] of your boy the first time no damage was done and no realization of danger exists, I guess there is a chance that the recurrence was somewhat self-motivated (lots of attention), would skew probability otherwise.

Clearly does NOT balance the fact that the center offered the opportunity AGAIN - no simple negligence IMHO (IANAL).

Find out if there were some other injuries before (other parents) and at least satisfy yourself (surprize visit or question a parent picking up their kid at the time injury occured) that the bleach matter is handled better now and stays that way.

Also, just trying out other centres won't traumatize your kid...