Laura Lopez used to work at the giant oil refinery at Azcapotzalco located in the northwestern part of Mexico City. For years she had watched the brown clouds pouring out of the plant’s huge smokestacks knowing that it was partially to blame for her husband’s respiratory infections, little Rosa’s nosebleeds, and her aging mother’s emphysema. Yet, she was proud to be working for a company as large and prestigious as many oil companies in the United States, proud that her country was finally able to join in the industrial revolution, and proud that she was able to earn high enough wages to help support her family’s comfortable life style.
Laura Lopez was very angry when the President of Mexico ordered the complete closed-down of the refinery. She and 5,000 other workers lost their jobs that day. She knew that the refinery provided 34% of the city’s gasoline and 85% of its diesel fuel, so she grew even angrier when she read in the newspaper that week that it would cost Mexico City $500 million a year for several years to import enough refined petroleum to make up for the closing of the plant. And, worst of all, she knew that many of her friends from work were not as fortunate as she was to have her husband still working; she and her family would be able to stay in Mexico City, while many people she had befriended over the years would be forced to find work in other parts of Mexico or the United States for much less money and no health benefits at all.


The reason that the President felt he had to shut down the Azcapotzalco refinery was because of what the locals called the Nata (bad). The factory smoke—filled with sulfur dioxide, nitrogen dioxide and ozone—combined with the carbon monoxide of Mexico City’s 15,000 run-down buses, 40,000 taxis and 3 million automobiles had gotten so bad that it formed a toxic mix that stung the eyes and made the air dangerous to breathe. Because the capital lies more than 7,000 ft above sea level, fossil fuels do not burn efficiently, producing more ozone than normal. During the calm winter months, the mountains that surround the city trap the polluted air close to the ground in atmospheric sandwiches known as thermal inversions. The President was worried that the Nata could become as deadly a thermal inversion as the one that killed 20 people in the steel-mill town of Donora, Pennsylvania in 1948 or the killer fog that claimed the lives of 4,000 people in industrial London in 1952.