AUSTIN (CBSDFW.COM) – Several state agencies exposed the personal information of 3.5 million Texans last year, including Social Security numbers.

The information was visible to the public for 15 months, the Texas Comptroller’s office said, from January 2010 until March 31, 2011.

Although the information was exposed in early 2010, the Comptroller’s office first acknowledged the exposure in a news release just today. “There was a lot of personal information,” explained R.J. DeSilva with the Comptroller’s office. “I mean it was names and addresses and there were also Social Security numbers and then uh, to varying degrees it also contained dates of birth or drivers license numbers.”

The agency says the information was exposed by the Teacher Retirement System of Texas, the Texas Workforce Commission, and the Employees Retirement System of Texas.

The data was exposed when those agencies were transmitting it to the Comptroller’s office.  As part of the transfer it was placed on a state server that was accessible to the public.

“We can’t emphasize enough how much we regret that this mistake happened,” said DeSilva. “It was human error that led to this.”

State rules require files that contain personal information to be encrypted, according to the Comptroller’s office.  The exposed information was not encrypted, the agency says.

The Comptroller’s office says there is no evidence that any of the personal information was misused.

In the statement, Texas Comptroller Susan Combs said, “We take information security very seriously, and this type of exposure will not happen again.”

Combs also says beginning Wednesday, April 13, her agency is sending letters to each person whose information was exposed.  The agency has also posted more information about the steps it is taking. You can also contact them toll-free at 1-855-474-2065.

The Comptroller’s office says it is working with the state Attorney General to investigate the exposure.

If you believe you have been a victim of identity theft the Better Business Bureau of Fort Worth advises you to:

• Place a fraud alert on your credit reports with each of the three credit bureaus: Experian, Equifax and TransUnion
• Close the accessed accounts
• File a police report

The Federal Trade Commission maintains a website with information on what to do if you think you have been a victim of identity theft.