Do you really think this hasn't been asked by Boston or any of the other very large Google Apps deployments? The answer is a single Google Search away...
> Google Apps for Government includes dozens of security features specifically designed to keep your data safe, secure and in your control. This segregated system, for government customers in the U.S. only, was the first cloud-based email application to receive FISMA accreditation from the U.S. federal government.
https://www.google.com/enterprise/apps/government/benefits.h...
> Google Apps for Government includes dozens of security features specifically designed to keep your data safe, secure and in your control. This segregated system, for government customers in the U.S. only, was the first cloud-based email application to receive FISMA accreditation from the U.S. federal government.