(Host) State government demanded an explanation on Tuesday for a series of outages that knocked out Internet service across Vermont.

Public Service Commissioner David O'Brien made the demand in a formal letter to Level 3 Communications.

That's a Colorado company that operates a vast telecommunications network that many companies and individuals rely on for their Internet and telephone service.

O'Brien says many consumers aren't even aware that they depend on Level 3.

(O'Brien) ''Every time you pick up your phone and you dial one and some area code somewhere else, you're utilizing that system. Or every time you open your computer email program and send an email off to a friend in another state or anywhere for that matter on the World Wide Web you're accessing the backbone network that Level 3 is a part of.''

(Host) There's been a failure in the Level 3 network 3 times in the past 3 weeks, including an outage of about a half hour Tuesday.

The failures made it impossible for customers to access the Internet or make long-distance telephone calls unless they had a backup.

So O'Brien wrote to Level 3 executives demanding answers to 21 questions ranging from the basic to the technical.

(O'Brien) ''For starters, we want to understand how this failure occurred in the first instance. We want to understand their ability to resolve this sort of thing and actually to keep this sort of failure from happening in the future.''

(Host) O'Brien says one of the state's major concerns is the apparent lack of redundancy in Level 3's network.

He says Level 3 is vital to telecommunications. So he says it should have backup systems that would kick in when a problem crops up.

O'Brien also wants to know why it has been so difficult for customers to get through to Level 3 during the outages.

VPR left a number of messages for Level 3 spokesmen, but they were not returned.

Click here to read Commissioner O'Brien's letter.