Peoples Gas says an employee of one of its vendors may have obtained and used the personal information of customers.
Customers who received the notice from Peoples Gas may need to take some steps on their own to avoid becoming a victim of identity theft.
Peoples Gas issued a statement saying a contracted employee was fired and may face criminal prosecution as a result of the breach. In the meantime, law enforcement and consumer advocates urge caution to everyone, especially this time of year when there tends to be an increase in complaints of identity theft.
According to the letter, a vendor's employee may have applied for credit cards using customers information. Peoples Gas will not say how many customers' information may have been compromised.
"Whenever there's a big data breach I think there's a message for both government and businesses that we need to do more and be careful and really exam what we keep, why we keep it, how long we keep it and why we need it at all," said the Federal Trade Commission's Steve Baker.
Baker says those whose information may have been compromised can become victims of identity theft -- when someone uses your personal information using in a scam to get money, open accounts or buy merchandise.
"Identity theft is out No. 1 source of all the complaints we get at the Federal Trade Commission," said Baker. "After climbing steeply for years, it may have leveled off, but it's still a massive problem."
Identity theft is also among the leading complaints to the Better Business Bureau of Chicago and Northern Illinois.
To detect identity theft, the BBB recommends getting your credit report at AnnualCreditReport.com to look for anything new that you don't recognize. Look at those monthly credit and debit card statements to make sure there is nothing unauthorized. Dispute errors with the credit bureaus as soon as possible.
"The longer you wait that you been a victim of identity theft, the harder it is to correct it," said Better Business Bureau's Steve Bernas. "Some people don't realize for years that their credit has been compromises, then try and clean it up, and it can take up to five, six, up to seven years."
Peoples Gas recommends those customers who were contacted to sign up for credit monitoring and put fraud alert on your credit report so no one other that you can open a new account.
The company declined would not provide details about when the information may have been compromised.