A loose toilet seat can cause injuries to both customers and employees.
Toilet seats should be checked daily to ensure they are secure and fastened.
Many things exist to help secure your toilets better including products like the below.
Screws that will not loosen
http://www.yukonseatgrip.com/
Add to bottom of toilet seat
http://dnlproductsinc.com/
Note: We are not aware of an approved product/solution. If you hear of one, please let us know so we can update this article.