Disaster effects might be far

Beyond the immediate effect and aftermath, industrial accidents may have a much longer timeline of causing disabilities and cancer, according to a study published this week from UC San Diego.

The Union Carbide chemical gas disaster in Bhopal, India in 1984 was one of the worst industrial disasters in history, killing thousands and causing injuries to hundreds of thousands. But its effects may still be unfolding today, the paper found.

The incident "may have led to men who were in utero at the time of the accident having a higher risk of developing disabilities and cancer later in life," said study corresponding author Gordon McCord, associate teaching professor at the UCSD School of Global Policy and Strategy. "The results also suggest that the Bhopal gas disaster affected people across a substantially more widespread area than has previously been demonstrated."

In Bhopal, a methyl isocyanate gas leak at a pesticide plant spread toxic gas for a 4.2-mile radius, exposing more than half a million people in the city of Bhopal to the gas and leading to up to 30,000 deaths in the region.

"There were serious long-term and chronic health consequences for hundreds of thousands of survivors, including respiratory, neurological, musculoskeletal, ophthalmic and endocrine impacts," said study co-author Prashant Bharadwaj, professor in UCSD's Department of Economics.

The toxins in the region's groundwater affected the reproductive health and other health outcomes of exposed women, impacting generations to follow, according to the findings.

At the time, studies found a fourfold increase in the rate of miscarriage following the gas leak, as well as increased risk of stillbirth and neonatal mortality.

The UC San Diego study researched the multigenerational impacts of such an event by looking at official health and education data — such as India's National Family Health Survey -- to estimate the long-term health effects (specifically adult cancer rates and disability) and the educational attainments of people who were exposed to the leaked gas in utero or as children in 1984.

"Our analysis of the results showed there were long-term, inter- generational impacts of the gas leak, showing that men who were in utero at the time whose mothers lived close to Bhopal were more likely to have a disability that affected their employment 15 years later," said study co-author, Anita Raj, a professor in the UC San Diego departments of Medicine and Education Studies and founding director of the campus's Center on Gender Equity and Health.

"They also had an eightfold higher cancer risk and lower educational attainment more than 30 years later, when compared to adults who were born before or after the disaster and who lived further away from Bhopal," she said.

Additionally, women who lived within 60 miles of Bhopal experienced a relative decrease in the birth of males compared with females in the 1985 group — 64 percent of children born from 1981 to 1984 were male, a proportion that dropped to 60 percent in 1985 — whereas women living beyond 60 miles had no difference in the sex ratio across the 1981-1984 and the 1985 groups.

According to the authors, the study had some limitations in that the people included would have had a range of actual exposure to the dangerous gas and the researchers’ calculations could be affected by migration and mortality.

"These results indicate social costs stemming from the Bhopal gas disaster that extend far beyond the mortality and morbidity experienced in the immediate aftermath," the authors write. "Quantifying these multi-generational impacts is important for policy consideration.

"Moreover, the evidence presented in this paper starkly highlights the long-term, inter-generational health and human capital effects of the Bhopal gas disaster and underscores the need for ongoing survivor support, as well as robust regulatory protection," they conclude.