UPDATED -- The U.S. House approved an amendment that would stop the Federal Motor Carrier Safety Administration from changing insurance minimums.

The amendment is a long way from becoming law but it highlights opposition to the agency even considering a change in the minimums.

The voice vote came Monday during consideration of the transportation appropriations bill. On Tuesday the House confirmed the voice vote by a narrow 214-212 margin.

Rep. Steve Daines, R-Mont., offered an amendment to cut off funding for the FMCSA rulemaking. He argued that the agency’s proposed rule would increase minimum carrier insurance levels by more than 500% when there is no proof that this would improve safety.

The current minimums, set in 1985, are $750,000 for general freight, $5 million for the most dangerous hazmats and $1 million for other hazmats.

Daines's amendment would in effect reverse earlier instructions from Congress to the agency.

In the 2012 highway law, MAP-21, Congress ordered the agency to analyze the situation. In its analysis the agency determined that the minimums need to be reviewed. It formed a team to draft a new rule and considers this a high priority.

The agency is considering a range of options but one would be to peg the minimums to the Consumer Price Index. If that happens, the general freight requirement would jump to $1.6 million, dangerous hazmats would go to $10.8 million and other hazmats would go to $2.2 million.

Daines said such changes would cut insurance availability.

“The bottom line is this,” he said. “The trial lawyers win, the small businesses lose.”

Two Representatives spoke against the amendment: Matthew Cartwright, D-Pa., and Ed Pastor, D-Ariz.

Cartwright is the author of a bill that would raise the $750,000 minimum to $4,422,000 and adjust it annually based on the medical CPI. That bill is separate from the appropriations process and would be considered later during debate over reauthorization of the federal highway program.

"When a truck is underinsured, when a truck doesn't have enough insurance to cover the harm that it causes, who pays the difference?" Cartwright said. "The U.S. taxpayer picks up the difference."

Daines's amendment succeeded on a voice vote but its future is far from clear. Presuming that the House clears the bill, it still has to be reconciled with the Senate bill, which at this point does not contain a companion provision. And Congress faces an uphill climb to finish the appropriations package before the end of the fiscal year in October.

Update adds House vote on Tuesday.