call the company and ask for the HR department
The quickest way, as David mentioned, is to contact the company. If this doesn't work, if you have an old account statement, contact the firm that administered the plan. They should have an account for you. If you don't have this, you can go to a website called freeERISA.com and search for the company's Form 5500. This is the filing that all 401k plans must file annually. On this, you should be able to find contact information. There are a few other steps beyond this, so if you don't get the information following these steps, let us know.
You need to do the research to find the plan administrator. If you can find an old statement, it would be on that. Call HR of EBV, ask for the plan administrator, but explain that it was several years ago. Be as specific as possible; ask if Energetic Solutions has the same 401(k) plan as is currently used by EBV Environmental.