The Washington Gas customer database may or may not have been compromised.  However, as well all know, utility deregulation now gives us a choice for natural gas suppliers.  Washington Gas will still deliver and bill us but another company may be the one actually supplying the gas to the system.  These calls may be coming from one of the many companies authorized as alternate gas suppliers for Wash Gas customers.  They may be using overseas call centers.  Since they are not actually your current gas supplier, they need your Wash Gas account number to switch you to them as your supplier.  Since the don't identify themselves upfront this is a blatant slamming attempt.  You will likely get locked into a long term contract that may initially reduce your bill but eventually cost more after they raise there price part way into the contract.  There will also be a hefty fee to switch back.  Get the name of this alternate supplier if you can and see if they are listed with Wash Gas and then check their website for all the details on their charges and plans.  Do not be pressured over the phone until you have had the chance to review everything about them including any BBB complaints against them.