The road to hell (which may simply be another name for some of the poorer places on this very earth) is often paved with the best intentions, they say. And this is probably more true of first world funded "development" projects in the third world than of most other human endeavors. The western/northern experts arrive in a poor nation of the global south, with cash and technology in hand, and hearts full of sympathy (let's give some of them the benefit of the doubt, and politely ignore some not-so-hidden corporate/colonialist agendas), wanting to do something, anything, to alleviate the suffering of the poor natives! They apply their expertise to identify at least one tractable problem, and find a technical solution which should improve quality of human life immensely. And indeed it does! The project is successful, people - especially children - start to live longer, the economy picks up, and the third world nation even begins to experience a miracle of development!!
So far so good.
So where does the killing chidren part come in? Deborah Blum has this sad story from one such "living" experiment - here's an excerpt:
There’s no surprise – and one might think, no news value – in the fact that prenatal arsenic exposure might pose a serious health risk. Except that this finding doesn’t derive from one more neatly controlled laboratory study. It comes from what I’m going to call a living experiment, in which the test subjects turn out to be human beings and those statistics about infant risk are actually based on tallying up dead children.

To explain: during the 1970s, international aid agencies came up with what seemed like a brilliant plan to stem a plague of water-borne illnesses in the Asian country of Bangladesh. Cholera, typhoid, dysentery were killing citizens by the thousand. As the pathogens responsible lived in surface water, public health officials decided the answer lay in cleaner supplies underground. Aid organizations joined together to install wells in disease-troubled villages, reaching down into the germ-free ground water below. They chose simple, relatively inexpensive tube wells, placed thousands of these over-sized drinking straws into the shallow aquifers.
At first, it seemed to work like a blessing. Infant mortality rates dropped by 50 percent as the rate of water-borne diseases dropped. But by the mid-1990s, a strange epidemic of other illnesses began to appear – some symptoms rather like cholera (lethargy, severe stomach pain, nausea and diarrhea), but others wickedly their own: such as a roughening and darkening of skin, a corrosion appearance of lesions on hands and feet:

In fact, as a team of researchers from adjacent India concluded in 1995: classic symptoms of arsenic poisoning. As it turned out, no one had done a good geological survey of the bedrock surrounding the aquifers. And with the best of intentions, the live-saving wells had been drilled into area unusually rich in naturally occurring arsenic.
Oops!!