LEAD POISONING in EL PASO


Terminology in article: Smelter
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aerial-asarco-image-from-national-archivesEl Paso, TX; Smeltertown, between Rio Grande and ASARCO

In 1970, following passage of the Clean Air Act, the City of El Paso sued Asarco over its sulfur dioxide emissions. During the process of discovery Asarco submitted documentation of its emissions to the city for the first time, Between 1969 and 1971 Asarco’s reports showed that it had emitted 1012 metric tons of lead, 508 metric tons of zinc, 11 metric tons of cadmium and one metric ton of arsenic (Landrigan, et al). On the basis of these documented emissions Bernard Rosenblum, Director of the El Paso City-County Health Department, estimated that 2700 persons between the ages of one and 19 would have blood lead levels at or above 40 micrograms per 100 milliliters—the safety standard for lead in blood at the time—and that residents within a four-mile radius of the smelter were likely to be affected. Alarmed, Dr. Rosenblum contacted the Communicable Disease Center (now the Centers for Disease Control) in Atlanta, Georgia, which sent Dr. Philip Landrigan and a team of researchers to investigate. Dr. Landrigan recalls that the National Academy of Sciences had just released a report stating:

It was well-known that certain smelters emitted lead, that it might be a problem for livestock living near smelters,but that people didn’t have to worry, that lead from smelters had never been shown to be a health hazard. So that was the context that surrounded our initial trip to El Paso.

The El Paso City/County Health Department had sampled air, soil and dust in a variety of locations. Dr. Landrigan’s team plotted the results in geographical relationship to the smelter.

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That first study established that the smelter was responsible for lead contamination in air, soil and dust. Based on these initial results, the CDC research team conducted a pilot study of blood lead levels in children attending a nursery school in Kern Place, a prosperous neighborhood located approximately a mile from Asarco’s smokestacks.

The blood lead standard at that time was 40 micrograms per deciliter. In other words, a level below 40 was thought be OK. A level above 40 was cause for concern. What we found in our pilot test of these children from the preschool nursery was that about 3/4 of them had blood lead levels above 40 micrograms per deciliter. That immediately set off alarms, because even in the worst inner city neighborhoods…we  had never seen 3/4 of the children with blood lead levels above 40.

Dr. Landrigan and his associates set up a plan to sample blood lead levels in children within approximately four miles of the smelter. They drew concentric circles around the smelter and divided them into zones: Zone One was set at a radius of approximately one mile from the smelter, and included the small Mexican-American community of Smeltertown, located immediately next to Asarco and almost directly under the smokestacks. Zone Two was set at a radius of about 2.5 miles, and Zone Three was set at approximately four miles. Dr. Landrigan recalls that in Zone One the team “knocked on every door…Zone Two was every second door, and ZoneThree…was every third or fourth door.” At each household blood samples were taken; soil, dust and paint samples were also taken; and if pottery was used in cooking, the pottery was tested for lead content.

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When the results were released Asarco argued that the lead did not come from the smelter, but from gasoline emissions along Interstate 10. But tests disproved this argument; the studies done by Dr. Landrigan’s team demonstrated that Asarco was responsible for the lead pollution found in Zones One, Two and Three. However, the researchers confronted another problem—the lack of studies demonstrating that the lead levels they had found could cause harm to children. The National Academy of Sciences study had asserted that lead from smelters was not harmful to human health.

In those days not too much was known about the toxicity of lead in children. Pediatric lead poisoning of course had been known since the early years of the 20th century…But lead poisoning was understood as an all or none disease. Either a child got terribly sick from a high-dose ingestion, or it wasn’t an issue. People treated it almost as if it was a common cold; either you’re sick or you’re not sick, and there was nothing in between.

The CDC team was asked by Dr. Rosenblum to design further tests to determine whether children in El Paso were damaged by their exposure to Asarco’s lead emissions. Meanwhile, other interests were converging on the El Paso lead controversy. The El Paso Pediatric Society issued a bulletin stating, “there is no evidence that there is a lead intoxication problem outside of Smeltertown” (quoted in Shapleigh 19). That same year the Lead Surveillance Committee of the El Paso County Medical Society announced, “any further massive blood lead sampling outside the Smeltertown-Old Fort Bliss area is at this time unjustified” (Shapleigh 19).

Asarco also commissioned its own study which was carried out by Dr. James McNeil, an El Paso pediatrician, and Dr. Potasnick, a psychologist from the El Paso School District. McNeil’s study, funded by the International Lead Zinc Research Association, a group connected to the metal industry, concluded that blood lead levels of 40 to 80 micrograms per deciliter were safe, provided a child received good nutrition. McNeil also supported Asarco’s claims that the children’s elevated lead levels were based on exposure to lead-based paint, rather than company emissions.*

In 1972 a Lead Surveillance Committee of the El Paso County Medical Society was formed. It included Dr. James McNeil, Dr. Bernard Rosenblum and Dr. Jorge Magaña, who would later become head of the City/County Health Department. The Lead Surveillance Committee took the position that further testing was unnecessary. They rejected a $50,000 grant from the CDC for Dr. Landrigan to continue his research. In 1973 they wrote the following letter to Dr. Landrigan:

I regret to inform you that our Board of Health unanimously voted to cancel the remaininlg portion of your study and in its place accept Dr. McNeil’s study from the International Lead Zinc Research Organization.

Dr. Landrigan recalls that the team had prepared a study design and returned to El Paso in the summer of 1973.

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The CDC team administered Wexler IQ tests and a finger-tapping test of physical reflexes to children. A group of children with blood lead levels below 40 was also tested, but examiners did not know which group each child belonged to.

We found a significant difference between the two groups of children. The children who had blood lead levels over 40 had an average IQ on the performance scale of the Wexler Test that was about 7 points lower than the children who had the lower blood lead levels. This was a very statistically significant detriment in the kids’ IQ.

We also found they had a much slower reaction time. We had a finger tapping test we had designed that counted how many taps  a child could do in 10 seconds. And we found that the children with the elevated blood levels were distinctly slower that their peers on this test.

Dr. Landrigan’s research, and the results produced by the CDC team, contributed significantly to scientific knowledge about lead. It is now widely accepted that lead is toxic at levels as low as 5 micrograms per deciliter. It is particularly damaging to the developing brains of children. Dr. Landrigan refers to this as “subclinical toxicity.”

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Sources:

* Dr. James McNeil Letter–Spanish version

  • Senator Eliot Shapleigh, Asarco in El Paso: September 2008
  • Interview with Dr. Philip Landrigan, September 2009, New York City, New York