Tina's Rosenberg's article in today's New York Times addresses the devastating impact that misguided bans of the pesticide DDT have had on people in developing nations. The New York Times presents the DDT issue as simply a serious policy mistake. But it's not simply a single mistake—it's part of a dangerous effort by environmental activists around the world to deprive people of various life-saving technologies. The DDT case alone should discredit these groups, yet they continue to have a harmful influence on public policy. Despite the problems DDT bans have caused, environmental activists have successfully advanced a worldwide ban on DDT under the Convention on Persistent Organic Pollutants (known as the POPs Treaty). The treaty has been ratified in enough nations for it to take effect, and the United States Senate plans to ratify it soon. It allows for only limited use of DDT on a temporary basis, and it creates serious regulatory hurdles that limit access in nations where people are dying in droves. The POPs treaty will also ban many other substances that might be useful in developing nations. In addition, international negotiators have set up a process to ban even more substances in the future under the POPs treaty. DDT is only one of many cases in which policymakers followed dangerous advice from environmental activists. But there are too many other examples as well. For one, some of these groups have advocated banning or restricting the use to chlorine—which disinfects water supplies and saves millions of lives every year. Rather than trying to undermine its use, the humane thing is to expand access in developing nations where millions die from dirty water. Instead, after officials followed activist advice in Peru in the early 1990s and reduced chlorination, thousands of people died in a cholera epidemic which spread rapidly because of inadequate disinfection. Activists also impede use of biotechnology, which could help feed starving populations. Their efforts have even led public officials in developing nations to impede access to food donated to starving populations because the food was developed with biotechnology. And environmental activists fight policies that would allow developing nations to grow economically—the one thing that will help the world's poor overcome starvation and sickness in the long run. It's surprising that environmental activists have not been completely discredited given their track record. Instead policymakers continue to follow their advice. That is much more than a small mistake—it's an outrage.