I have an indoor bin. It is one of the large storage bins with holes drilled for air circulation. It has the tendency to get wet, but I take the lid off for evaporation when I notice this and sometimes put in dry oatmeal to absorb excess water. The worms were thriving, then suddenly they all died. It was not too wet. A nature center I volunteer for near me had a similar setup and they said when they put something in their worms all died, but they didn't remember what it was. I'm worried that I inadvertently added that same ingredient to my bin and caused the die-off. Is there something that is toxic to worms? My main suspect is celery because there was some untouched celery in the bin when I checked after I noticed the die-off.

Their main food was potato/sweet potato/carrot peelings.