The exposure of children to toxic lead, and the subsequent declines in IQ and earning potential, costs the developing world nearly $1 trillion annually, according to a new report. Based on the average lead levels in children under the age of 5, researchers from New York University found that Africa suffers the greatest costs from lead exposure, losing an estimated $137.7 billion annually, or about 4 percent of its gross domestic product (GDP). In Latin America, the costs are about $142.3 billion, the study found, while in Asian nations the costs are about $699.9 billion. By comparison, the annual costs in the U.S. and Europe, where exposure to lead has decreased significantly in recent decades, are about $50 billion and $55 billion, respectively. The report said lead consumption has increased worldwide since the early 1970s, largely because of rising demand for lead batteries. The study was published in Environmental Health Perspectives.