Private businesses such as rental and mortgage companies and car dealers are checking the names of customers against a list of suspected terrorists and drug traffickers made publicly available by the Treasury Department, sometimes denying services to ordinary people whose names are similar to those on the list.

The Office of Foreign Asset Control's list of "specially designated nationals" has long been used by banks and other financial institutions to block financial transactions of drug dealers and other criminals. But an executive order issued by President Bush after the Sept. 11, 2001, attacks has expanded the list and its consequences in unforeseen ways. Businesses have used it to screen applicants for home and car loans, apartments and even exercise equipment, according to interviews and a report by the Lawyers' Committee for Civil Rights of the San Francisco Bay Area to be issued Tuesday.

"The way in which the list is being used goes far beyond contexts in which it has a link to national security," said Shirin Sinnar, the report's author. "The government is effectively conscripting private businesses into the war on terrorism but doing so without making sure that businesses don't trample on individual rights."