The clamor to crack down on banks that allow their accounts to be used to launder drug money has been growing for years.

Now there is growing sentiment along the U.S.-Mexico border that vigilance has gone too far and is hurting law-abiding businesses. American banks, wary of the potential for massive penalties, have closed Mexican accounts or saddled customers with new restrictions.

The challenge is particularly acute for Mexican companies whose customers pay dollars. In Mexico, banks refuse to take their greenbacks even after the government lifted 4-year-old caps on cash deposits of the U.S. currency in September.

Sens. Jeff Flake and John McCain, both Arizona Republicans, called for hearings in February, saying security concerns should be balanced against the need for access to banks in border communities.