WASHINGTON - Credit card industry practices are being denounced by some in Congress, especially raising customers' interest rates whose credit ratings decline, even if they pay card bills on time.

Sen. Carl Levin, D-Mich., chairman of a Senate Homeland Security and Governmental Affairs subcommittee, is holding out the club of possible legislation to spur voluntary changes.

With Americans weighed down by some $900 billion in credit card debt - an average $2,200 per household - practices of the very profitable industry have been ripe for scrutiny by the Democratic-controlled Congress.

Today, Levin's subcommittee, which has been investigating the industry, will look at how credit-card issuers raise consumers' rates, to as high as 30 percent, when their so-called FICO credit scores decline even if they've paid credit card bills regularly and promptly. In many cases, consumers have little notice of the increased rate, which are automatically triggered by declines in FICO scores for reasons left unexplained, the subcommittee found.

In an e-mailed response, a spokesman for the American Bankers Association, which represents the banking industry, said: "Costs for nearly every product can change, be it because consumer's risk profiles change or because underlying costs change. Credit cards are no different." *