For years, the wealthy nations of the world have been dumping their massive old ships on poor countries, leaving the extremely hazardous work of breaking them down to workers elsewhere. About 4,000 civilian and military ships are slated to go out of service each year. “Only a fraction of the world fleet is being recycled properly,” said Niko Wijnolst, chair of the Dutch Maritime Network. Many of the ships end up in India and Bangladesh, where workers without helmets, protective glasses, or even shoes deal with the explosive gases, PCBs, asbestos, and other toxins that make up the vessels. A conference last week in Philadelphia explored ways to turn shipbreaking into a more reputable industry and reduce the environmental and health risks associated with it.