BURNING UP THE ROAD

AS SOON AS THEY SAW THE PLUME OF gas, the Mexican truck drivers leaped out of their cabs and ran for the American side of the border. Acrylic acid, a toxic chemical, had leaked from a tanker waiting in line for U.S. Customs inspection, and the liquid was vaporizing as it gathered in a noxious pool. It was "chewing holes in the pavement," says Lee Thompson, who saw it all happen in early November at the border station outside Laredo, Texas. His hazardous-materials response team, fortuitously on the scene for a training exercise, rushed to prevent the highly flammable acid from catching fire. They barely averted an explosion. In the past few months, several Mexican trucks traveling just inside the U.S. border have exploded or leaked toxins that threatened Texas' water supplies. Says Thompson: "I would love not to have to respond to these spills--there is enough pollution down here."

Thompson may not get his wish--and the spills and explosions are likely to occur farther and farther north of the border. The poorly supervised Mexican trucks already roam a 15-mile zone in southern Texas. On Dec. 18, under provisions of the North American Free Trade Agreement, Mexican trucks will gain free access to U.S. highways in border states, just as U.S. trucks will have access to Mexico's northern highways. It's an aspect of NAFTA that is prompting second thoughts. Pro-NAFTA Texas Attorney General Dan Morales warns that unless the Federal Government takes action, there will be danger of a spill occurring in a metropolitan area: "This deadly cargo, carried under such conditions, is nothing short of a time bomb."

Almost 75% of the $100 billion in U.S. trade with Mexico is delivered by truck, and most of that cargo travels through Texas. The major route is Interstate 35, running north-south through several of the state's major cities--San Antonio, Austin and Dallas-Forth Worth. Specialized trucking firms called drayage companies haul goods in a narrow strip of U.S. territory along the border, where they exchange cargoes for transshipment to border plants or destinations deeper in America. The majority of trucks are Mexican because U.S. companies, afraid of theft and corruption, are reluctant to send their trucks into Mexico. More than a fourth of the approximately 5,000 Mexican trucks crossing into Texas every day carry corrosives, chemicals, explosives, jet fuel and pesticides, according to Morales. While many trucks keep within guidelines, the volume makes it impossible for authorities to monitor the trucks closely.

On an average day, at least 4,000 Mexican trucks cross the Juarez-Lincoln International Bridge in downtown Laredo, where only 20 customs agents are available to work the import dock. Those agents have to inspect insurance, driver's licenses and immigration papers and look for narcotics and violations of trade-compliance laws. Checking a vehicle for faulty brakes or bald tires is way down the list and not necessarily a customs agent's responsibility, according to chief inspector David Higgerson, the cargo director for U.S. Customs in southern Texas.