In one of the largest consumer payouts of its type, MoneyGram International Inc. has agreed to fork over $18 million to the Federal Trade Commission to settle charges that it knowingly allowed its operation to be used by con artists to swindle U.S. consumers out of millions of dollars.

“This is a pretty significant amount of money to return to consumers,” said FTC Chairman Jon Leibowitz.

The money the FTC is getting from MoneyGram will go directly to provide relief to victims. If you’ve been one, call 202-326-3755. The payout will be on a pro rata, or calculated, basis. The FTC is still working on how to verify claims and when people will be paid.

The FTC alleged that MoneyGram knew that its system was being used to defraud people but didn’t do enough about it, and that in some cases MoneyGram agents actually participated in the schemes.

The FTC said that from 2004 and 2008, telemarketers and others using MoneyGram’s system convinced consumers to wire them more than $84 million within the United States and to Canada. And that’s just what people reported they lost. The actual amount could be much higher.

“They (MoneyGram) were involved in facilitating all these transfers,” Leibowitz said. “It was easier to go after them than the individual scammers.”

MoneyGram did not admit to any wrongdoing.

“We do not want to get into discussions about the individual allegations made by the FTC,” Lynda Michielutti, MoneyGram’s director of corporate communications, wrote to me. “Suffice to say, we do not agree with the FTC’s claims.

“However, we believed that it was in the best interest of our company and our consumers to put this matter behind us and focus our resources on delivering our valued service to consumers rather than battling it out through a long and costly trial.”

Crooks use a number of schemes that involve money transfers through companies such as Western Union and MoneyGram, the FTC says. Money transfers are virtually the same as sending cash. Once you make a transaction, there is no way you can reverse it or trace the money.

The FTC said a survey found that at least 79 percent of all MoneyGram transfers of $1,000 or more from the United States to Canada over a four-month period in 2007 were fraud-related.

In one type of money wire scheme, someone receives a notice that he or she has won thousands of dollars in a lottery. But to collect the money, the person is told to pay a fee for taxes or customs, or to have a third party collect the winnings.

In another twist on this con, someone is told they are being hired to visit stores to evaluate MoneyGram money transfer operations. In this elaborate ruse, the con artists send consumers a cashier’s check, telling them to deposit it in their checking account, and then send most of the money back using a money transfer location. Initially, the check might clear. But later when the victim’s bank discovers the deception, the person is on the hook for the fraudulent check.

The FTC’s complaint alleges that MoneyGram disregarded warnings from law enforcement officials and even its own employees that rampant fraud was being conducted over its network. The Minneapolis-based MoneyGram has 180,000 agents with locations in nearly 190 countries and territories.