WASHINGTON — Legislation introduced Wednesday in Congress would make it harder for U.S. vehicle-safety regulators to become lobbyists for auto makers, a key issue raised by the Toyota Motor Corp. safety recalls, The Wall Street Journal reported.

The bill, introduced by Sen. Barbara Boxer (D., Calif.), would prohibit auto-safety regulators from working for car companies in any job that required contact with their former agency for three years after leaving their government jobs.

The proposal responds to lawmakers' concerns that Toyota employed former auto-safety regulators who directly dealt with their previous employer, the National Highway Traffic Safety Administration, on issues relating to vehicle defects.

Transportation Department officials have said they have found no ethics violations in dealings between Toyota lobbyists and regulators relating to the company's recall of 8 million vehicles globally for gas-pedal and sudden-acceleration issues.

But some consumer advocates, along with Transportation Secretary Ray LaHood, have said they are troubled by the prospect of a "cozy relationship" between car-industry lobbyists and their former colleagues at NHTSA, and have called for tighter ethics laws.

"I am deeply concerned about the all-too-cozy relationship between former NHTSA officials and the auto industry," said Boxer, the Senate Environment and Public Works Committee chairwoman. "My legislation would address this 'revolving door' by preventing auto makers from having undue influence on agency decisions."

Under her bill, individual violators would face fines of $55,000, and manufacturers would face a civil fine of $100,000. Those penalties are in place for current ethics laws.