when buying a business what obligation do I have to the current
employees who have been there 10 years

The answer depends on whether it is a share or asset purchase, and whether those employees have signed employment contracts. If you are planning on letting those employee go, they are likely entitled to significant amounts of severance. In the circumstances, it is extremely important that you get legal advice from an experienced employment lawyer. Give us a call at the number below to set up a confidential consultation.