I need help with a few multi media liability law questions

[Journey]

My partners and I have a school bus safety book for Pre K - 3 we would like to market to school systems. We have realized we need multi media liability insurance. This is quite cost prohibitive for us at this time.

My question is:
If we sell units to a school system now, and a year or more later, an accident occurrs and our material is found instrumental in some way, are we liable? If we would let our insurance lapse after a few years are we personally or our LLC liable because our safety program is still utilized in that school system?

I hope these questions make sense. We need to know if we should just submit to an educational publisher or market our program ourselves.

Thank you in advance for any help you can give me.

Normally if the company is the one contracting and you don't sign personally as well, then just the company is liable not you personally.