NEW YORK (CNN/Money) - Twenty-five percent of credit reports contain errors serious enough to deny consumers access to credit, favorable loan rates and in some cases a job, a new study said Thursday.

"It is outrageous that inaccurate credit reports could damage one in four consumer's ability to buy a home, rent an apartment, obtain credit, open a bank account, or even get a job," Ed Mierzwinski, director of consumer programs at consumer group PIRG, said in a statement.

The report defined "serious" errors as those that could result in an automatic denial of credit, such as incorrectly marking accounts as delinquent or in collection.

Some of the key findings in the study conducted by PIRG include:

• Fifty-four percent of the credit reports sampled contained personal information that was misspelled, outdated or belonged to a stranger. One report, for example, listed a consumer's birth year as 1952, when she was actually born in 1975.
• Thirty-percent of those reports contained credit accounts that had been closed by the consumer but were still listed as open. Incorrectly listing closed accounts as open gives creditors the impression a consumer's credit is over-extended.
• Twenty-two percent of the reports had the same mortgage or loan listed twice. Again, this gives creditors the impression a person has over-extended his credit, or is delinquent on one loan.
• In all, seventy-nine percent of the credit reports sampled contained errors of some kind.

A spokesperson for a credit industry trade group disputed the claims, saying that credit decisions are based on a consumer's overall credit report and that one negative claim may not have significant impact on the total score.

He also noted that under federal laws credit reporting errors must be corrected within 30 days.

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"I don't think there ought to be an error in any credit, but we update credit files 4.5 billion times a month," said Norm Magnuson, vice president of public affairs for the Consumer Data Industry Association. "When there is an error, it is our obligation to correct it, which in 80 percent of the cases is done in 10 working days."

PIRG recommends that consumers examine their credit reports at least once a year, noting that the three major credit bureaus--Equifax, Experian, and TransUnion--maintain files on nearly 90 percent of all American adults.

The report also took aim at the Fair and Accurate Credit Transactions Act (FAIR Act) of 2003, which grants consumers the right to request a free credit report each year. The FAIR Act, finalized June 4, 2004, allows credit agencies to gradually roll out the program over a nine-month period, beginning in December for those who live on the West Coast before ending on the East Coast in September 2005.

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California, Colorado, Georgia, Maine, Maryland, Massachusetts, New Jersey, and Vermont already have laws requiring credit agencies to provide their residents with one free report a year.

PIRG's report is based on 197 surveys received from 154 adults in 30 states. PIRG collected 73 surveys from Equifax, 60 from Experian, and 40 from TransUnion. Five of the responses did not indicate the credit bureau and 19 indicated the respondent ordered a report from all three bureaus.