There is a street called Chemical Row in Matamoros, the shabby Mexican town across the border from Brownsville, Texas, which is lined with some of the most hazardous industries known to man.

A long, corrugated-iron shack, now rusting with neglect, was once a lead smelter owned by Asarco, the US metals group. Behind it is a pesticide plant owned by a company based in Illinois. Further down the row, subsidiaries of US multinationals produce fertilisers, wood hardeners, and more insecticides. These and other maquiladoras, Mexico’s tax-exempt manufacturing plants, were sued in 1992 by a group of Brownsville families whose children were still-born with the rare condition known as anencephaly: deformed skulls with no brain.

The families blamed airborne pollution from Matamoros factories and, in an out-of-court settlement last year, they accepted compensation believed to have been in the region of $ 25m.

At the end of Chemical Row, looming over the flat landscape of the Rio Grande valley, is Quimica Fluor, a joint venture between E I Du Pont de Nemours and Mr Carlos Slim, Mexico’s telecommunications magnate, which makes sulphuric and hydrofluoric acid.

Quimica Fluor and Asarco have become the subject of a new legal battle in the US, this time brought by Mexican families whose children were born with deformities. For many years Quimica Fluor compensated neighbouring sorghum farmers for their withered crops, but the payments stopped in 1988, when a government decree created an “indemnity buffer zone” around the plant. The farmers, however, continue to live and work on heavily contaminated ground.

The North American Free Trade Agreement, which Mexico joined in January 1994, was meant to address the environmental degradation of the 2,000-mile Mexico-US border. Nafta’s proponents argued that lower tariffs would eliminate the tax advantages of the border maquiladora industry and promote industrialisation further inland.

However, industrial growth on the Mexican side of the border has, if anything, accelerated. Devaluation of the peso in December 1994 lowered manufacturing wages in Mexico to a tenth of those in the US, further encouraging US companies to relocate their assembly operations. Since then maquiladora employment on the border has surged by 50 per cent to almost 665,000. Shanty towns have sprouted around hastily built industrial parks, water is scarce, and drainage and sewerage are non-existent.

Although US companies will not admit it, another reason for locating in Mexico is the weak enforcement of environmental laws. Matamoros, with more than 100 maquiladoras, has only three government health and safety inspectors, who normally give advance warning of factory visits. Air quality and industrial effluents are tested only once a year.

The unfettered growth along the border and the perceived loss of US jobs to Mexico’s maquiladoras have alarmed US congressmen and environmental groups. Senator Richard Gephardt, who visited the border earlier this year, wrote to fellow Democrats, saying: “We saw 21st century technology combined with 19th century living and working conditions.

“We drove by industrial parks where companies continue to dump their toxic wastes at night into rivers. We saw furniture plants using highly toxic solvents and finishes that once operated in California and throughout the US, and which had moved to Mexico because of lax environmental enforcement.”

Last month a group of women from the Philips Electronics Airpax plant in Matamoros gathered at a church hall to discuss their health concerns following the death of one of their colleagues, Mrs Ana Maria Sanchez, who was 38.

The company, which ordered the autopsy, told employees she had died of a heart attack, but doubts remain.

“The women assemble electronic components with soldering wire which contains lead, and lead fumes are a known cause of brain haemorrhages,” says Mr Domingo Gonzalez, an environmental activist with the Texas Centre for Policy Studies.

One after another the women at the meeting rose to complain of severe headaches, high blood pressure and eye infections. The stench at the plant was sometimes unbearable, they said. They suspected that air extractors were not working properly, but their complaints had gone unheeded.

Mr Tarex Haidar, Airpax’s general manager in Matamoros, expressed surprise when told of his employees’ concerns. Air filters were checked on a weekly basis, he said, and protective masks were available on request. “We have never had a known case of lead poisoning, and we employ a doctor on site to attend to any medical problems the women may have.”

Following increased scrutiny by US environmental groups and the growing threat of litigation, some maquiladoras have installed water treatment plants and better air filtering systems. But these remain the exception among the 2,000 on the border.

The US Environmental Protection Agency has also launched a computerised tracking system to monitor hazardous materials employed by US-owned maquiladoras, which by law must be transported back to the US for proper disposal.

“Before ‘Haztraks’, we didn’t have a clue about who was generating toxic waste, how much of it existed, or where it was going,” says Mr Joseph Schultes of the EPA in Dallas. “Now we can correlate shipments from the cradle to the grave.”

The border’s soaring health and environmental problems, however, appear to have overwhelmed auth-orities in both countries.

An $ 8bn border clean-up plan, promised by President Bill Clinton in 1993 to win over environmentalists to the Nafta cause, has been slow to materialise.

Two binational entities set up to promote border infrastructure development – the Border Environment Co-operation Commission and the North American Development Bank – have experienced teething problems. To date Nadbank has approved financing for only four small projects.

Mexico’s commitment to the joint programme, meanwhile, has dwindled with its economic crisis. Investment in basic sanitation fell from $ 235m in 1994 to $ 24m in 1995 and $ 55m last year, according to environment ministry estimates.

Former Nafta supporters such as Sen Gephardt believe the treaty “simply isn’t working”. The clean-up of the border has not occurred. The health of border residents has deteriorated. Nafta does not have the power to oblige Mexico to enforce its environmental laws. But the southward migration of US manufacturing plants continues apace.

Leslie Crawford ..RT.- On July 1 the Clinton administration presents its report on Nafta’s first three years amid fierce debate between the champions of free trade and those who fear US jobs are being lost to Mexico’s low wage, low pollution-control economy. In a series of articles we analyse the issues.