Thank you for the information and your question. Most workers compensation policies cover any worker, whether an employee or not, including independent contractors and unpaid labor, under their policies. So, the first thing you should do is read, or have your attorney read, your policy in detail. It would be unusual for the carrier not to cover the situation you described if it happened in the workplace.
If, by some chance, the policies definitely excludes the type of worker this was, then if you have a general liability policy for your Company that covers other types of incidents, for example customers or visitors who are injured on your property or by your employees, then you need to contact them. If, for some reason, you don't have such a policy and don't have an umbrella policy for your home that might cover them, you (or the corporation if you are incorporated) will be responsible for the damages which occurred. If the latter situation applies, I would strongly urge you to get a local attorney involved in negotiating a settlement of the damages.
Please feel free to ask follow up questions if you have them. If none, then if you could take a moment to leave a positive rating in the box above, I will receive credit for assisting you today. Thank you