Spooked by the possibility of identity theft, increasing numbers of people are taking a radical approach to thwart criminals: They are putting their credit reports on permanent freeze.

A frozen credit report prevents almost anyone from using your name to take out a loan or sign up for credit, such as a credit card, a bank account or cell phone service. That is because, with a freeze in place, potential new creditors can't get access to your credit record kept on file by the three main credit-reporting bureaus without your explicit permission.

Michael Dana, a Dallas police detective, chose to freeze his credit reports after a Texas law took effect last month that made freezes available to all residents. Dana says he received several notices from financial institutions and the government saying that some of his personal information may have been compromised. "You can try to shred all your documents," says the 42-year-old. But "I'd rather shut my credit down and have the best security in place and not be a victim at all."

An estimated 50,000 to 70,000 people have so far signed up for credit freezes, according to the Consumer Data Industry Association, a trade group that includes the three credit bureaus. Consumer groups expect that number will grow after the bureaus - Experian Group Ltd., TransUnion LLC and Equifax Inc. - recently announced plans to offer credit freezes nationwide.

The bureaus' action comes after 39 states and the District of Columbia enacted laws in recent years allowing consumers to freeze their credit, though some states limit the option only to identity-theft victims.

Florida enacted a credit-freeze law last year, and Jimmy Glass and his wife signed up the same day. "Just the thought of someone else being able to assume your identity and rack up thousands of dollars in your name - that's just unthinkable," says Glass, of Orlando. "I have all the credit cards I need, no mortgage and no need for any car loans, so I just decided to shut it down."

Freezing your credit can be cumbersome. You generally have to write a letter to each of the credit bureaus and pay a fee of about $10 to each. Although you can temporarily suspend the freeze, doing so could take several days and, in many cases, means paying more fees.

When your file is frozen, the bureaus assign you a personal identification number, which you will need to remove the freeze from the file. To lift the freeze, you must notify the bureaus and specify the amount of time you want the lift in effect. With a fee of $10 per bureau in many states, it can cost a married couple as much as $60 to initiate a freeze across all three bureaus and another $60 to lift the freeze. Freezes are typically free for people who provide a police report confirming they were victims of identity theft.

The credit bureaus are generally promising to lift a credit freeze within three business days of receiving the request. But some states are forcing them to go further. Beginning next year, Utah and the District of Columbia, for instance, will require the bureaus to lift the freezes for state residents within 15 minutes.

Some states also are requiring the credit bureaus to charge lower fees in their states. As of last month, Indiana residents can request, lift or a remove a freeze for free, while consumers in other places, such as Nebraska and Delaware, pay only a one-time fee to place the freeze with no additional costs to remove the freeze. Some states, including New York, New Jersey and Montana, require that bureaus charge fees of $5 or less.

Consumers can get more information on states' credit-freeze laws, along with general guidelines on how to place a freeze, at www.financialprivacynow.org, a site run by Consumers Union.

The strategy isn't a total answer to identity theft: for example, a freeze won't stop someone from stealing your existing credit-card numbers and using them fraudulently. A freeze also doesn't prevent existing creditors and certain government or state and local agencies from accessing your credit files.

Identity-theft experts say that freezes are often best-suited for people who have little need to apply for new credit, such as children or for elderly parents, or for those who have already paid off their mortgages, car loans and credit cards. Even with a freeze in place, consumers can still order their own credit report. A freeze also doesn't lower an individual's credit scores.