MATAMOROS, Mexico -- On one side of Ernestina Sanchez de Martinez's street is the Retzloff pesticide plant, emitting pungent fumes in which her children play. A chemical leak in 1983 forced authorities to empty the area, destroy pets and bury wash hanging on clothes lines.
On the other side of Mrs. Sanchez's street is the U.S.-owned Stepan plant, which makes foaming agents for shampoos. The plant has a history of illegally dumping waste. Last summer, a few days after neighbors were given a goodwill tour, a mixing tank exploded, shattering windows and confidence.
"They have destroyed the soil," Mrs. Sanchez said of the two factories. "Almost nothing will grow here. But we are not scientists and do not know what chemicals have drained onto our land."
Indeed, much about the plants is a mystery to the 23 families in Los Uniones, a former rural hamlet now straddled by the two factories.
Unlike U.S. citizens, Mexicans have no legal right to know what is being manufactured a few feet from their doorsteps. And Los Uniones residents have been unsuccessful in forcing the plants to move.
The neighborhood's frustration with the companies underscores a bitter belief here that the average Mexican is helpless when it comes to controlling his environment.
Like other Mexican cities along the U.S. border, Matamoros is filled with factories and assembly plants that have fouled the water, air and soil. More than 80 companies, mostly U.S.-owned, were lured here by low wages, tariff exemptions and lax enforcement of labor and environmental standards.
While the plants have created an economic boom over the last three decades, they have also created an ecological mess. Critics have raised fears that even more industrial polluters would come if Mexico, the United States and Canada reach agreement on a new trade pact now under negotiation.
Largely to assuage demands that the trade pact contain environmental restrictions, Mexico has agreed to spend $400 million for a border cleanup, with $13 million earmarked for Matamoros.
But the change in government attitude is too late for some Mexicans, who have gone to court in the United States.
In October, for example, more than 60 Mexican children sued a U.S. company in neighboring Brownsville, Texas. The children are deformed or retarded.
Lawyers contend that their birth defects were caused by chemicals used by their mothers when they worked in a plant owned by Mallory Capacitor Co. of Indianapolis.
Although the Mallory plant here closed in 1977, the suit is trying to determine who assumed its liability among several successive owners.
"They exploited these women, gave them no protection, no masks or gloves and above all no warning about what kinds of chemicals they were using," said Richard L. Palmer, a Brownsville lawyer representing many of the children. "The bill .. has come due."
Other Mexicans have sued U.S. manufacturers in California over workplace conditions.
Mexican laws limit a company's liability to a tiny fraction of what a worker would receive in a U.S. court or under workers' compensation.
It's not clear yet how much success the Mexicans will have pressing their claims, some of which hinge on complicated scientific issues.
Still, the lawsuits offer hope to Mexicans who feel that their government won't get tough with the U.S. employers.
Workers in Matamoros, for example, say the companies deliberately underreport work accidents to hold down the cost of insurance with Social Security, the Mexican agency that provides medical benefits for industrial workers.
Zenith, for example, said its plant was accident-free in 1990, but later amended that claim when a reporter cited two serious accidents that harmed workers.
Reports on the accidents were never filed with Social Security, which uses them to determine a company's insurance rate.
"The Mexican government is in bed with the companies because they are afraid they will leave," said Dora Elia Ramos, a 34-year-old Zenith worker. "I went four times to the doctor at the Social Security hospital to complain of solder fumes, and each time he told me to give up smoking.
"The problem is I have never smoked," she said.
Sometimes, the simmering frustration with U.S. businesses erupts into anger.
Last November, a volunteer ambulance driver and some firefighters were barred from a U.S.-owned plant during a chemical accident that sent six Mexicans from a nearby factory to the hospital.
"These American companies are playing with Mexican lives!" the driver shouted.