A U.S. Senate decision to block funding for a test program to let Mexico's long-haul trucks operate in the United States uses outdated safety fears to mask protectionism, Mexican truckers and the U.S. government say.

A truck crash in the desert of northern Mexico killed dozens last weekend when a cargo of explosives blew up, creating a huge fireball and crater in the road.

That helped influence the U.S. Senate when it voted on Tuesday to block funding for a test program to let Mexican long-haul trucks operate in the United States under 1994's North American Free Trade Agreement.

But Mexican truckers and the Bush administration say that kind of accident would not happen to Mexican trucks in the United States under the program.

The 600 rigs that were due to take part in the one-year plan were new vehicles and safety checks on the U.S-Mexico border were tougher than for U.S. truck drivers.

Checks are so tight that only one truck, from Mexico's northern city of Monterrey made it deep into the United States in the five days the project lasted.

The truck took steel to North Carolina last weekend before strong pressure from well-paid U.S truckers suspended the funding on Tuesday night. The Bush administration says it will try to convince Congress to rethink the decision to block funding and could veto the broad spending transportation bill approved on Tuesday night.

Calling the decision a "sad victory for the politics of fear and protectionism," John Hill, a director at the U.S. Federal Motor Carrier Safety Administration, echoed frustration at what Mexican business leaders see as hypocritical behavior from the United States, the main promoter of free trade in the Americas.

"Safety is not an issue. The truck that went from Monterrey to North Carolina was a 2007 Freightliner made in the United States imported into Mexico," said Fernando Paez, whose Transportes Olympic was the first Mexican company to win U.S. approval under the pilot plan promoted by U.S. President George W. Bush.

The NAFTA trade deal requires open borders for long-haul vehicles, but the United States, citing safety concerns, has limited Mexican trucks to U.S. border cities like San Diego since 1982.

Some 70 percent of the U.S.-Mexico $330 billion annual trade flow goes by road. Free roaming for trucks could save consumers in both countries over $400 million a year in transport costs, according to the U.S. Embassy in Mexico.

SAFETY "MYTHS"

Gustavo Gonzalez, a director of Mexico's truckers association Canacar, said safety concerns were "myths" and Mexico had a similar safety record for long-haul cargo vehicles as the United States.

"The older trucks we use for transfers at the border are not those that we would use on U.S. roads. Our best trucks cost 10 times that of the transfer vehicles," Gonzalez said.

But the U.S. Teamsters union, fearful of job losses among its 100,000 long-haul drivers, said the fiery truck accident in Coahuila in Mexico "demonstrated a lack of safety standards."

"This is about greed, about Mexican business who want to use lower-paid truck drivers to get us their commerce as cheaply as possible despite the risks," Teamsters' General President Jim Hoffa told Reuters.

Robert West, an Americas trade expert at Global Insight consultancy, said U.S. lawmakers' resistance to the Bush truckers plan was more about politics and double standards in Washington. "Congress' position is duplicitous and sets back the time when the border will be truly open, as it should be under NAFTA," he said.

George W. Bush U.S. Mexico Safety