Your biggest problem is going to be the statute of limitations on any claim, whether a breach of contract, negligence or breach of warranty claim. (Depending on nature of the claim, limitations period might be 2, 5 or 10 years). It sounds as if these issues have been known for some time. When were they first discovered and identified as the contractors' fault? Why wasn't action immediately taken? Since you are a public utility, speak to either the utility's general counsel or that of the agency that controls your utility about your concerns and see if you can proceed against the contractor under the 10 year statute of limitations perios of WV Code 55-2-6 or 55-2-6a.
To questioners from West Virginia & New York: Although I am licensed to practice in your state, I practice on a day-to-day basis in Massachusetts. I answer questions in your state in areas of the law in which I practice, and in which I feel comfortable trying to offer you assistance based on my knowledge of specific statutes in your state and/or general principles applicable in all states. It is always best, however, to work with attorneys and court personnel in your own area to deal with specific problems and factual situations.