The DOE gave details of the attack on Wednesday and announced that it would be providing credit-monitoring and identity theft prevention tools to all past and present employees who may have been affected. The DOE claims that no classified information was stolen, but the PII that was stolen could be used to access other government systems.
This is actually the second DOE hack this year - the first one occurring back in February. The previous hack was less severe with only a few hundred employee profiles being accessed. Regardless, that's a government organization that's been hacked twice in one year and it just so happens to be an organization that deals with nuclear weapons.
via The Verge