"The first confirmed report of arsenic contamination of tubewell water came as early as 1983, but it was regarded as an isolated incident. … By 1987, more than 1,000 cases had been identified. … Organised conferences and pleas for attention fell on the deaf ears of aid officials and government workers, who pointed to the obvious health benefits. The installation of the tubewells continued to accelerate. Cases of arsenic poisoning began to appear in Bangladesh, where the problem was found to be even more severe than in West Bengal. How the water came to contain such high levels of arsenic is still a matter for conjecture. Why the distribution of arsenic contamination is so maddeningly random is still not known. … Much deeper tubewells were more likely to be safe but were more expensive, and replacing the hundreds of thousands of contaminated shallow tubewells could take years."