Who, according to Sharia, guarantees the workers' accidental destruction of another's property: the workers or the employer?

What the private contractor (Ajeer Khas) does not guarantee is what perishes under his hand from the employer's (Musta'jir's) property without transgression or negligence, because he is the owner's deputy and a trustee with him. As for the shared contractor (Ajeer Mushtarak), he guarantees what perishes with him due to transgression or negligence. The contractor's offense against another's property is guaranteed by the contractor himself, and the employer has no relation to it.