Dubai: The iPhone 5 is ranked higher than Samsung Galaxy S 111 on toxic chemicals used in phones, according to a study by Ann Arbor-based Ecology Centre and ifixit.

Analysis of the chemicals used in modern smartphones has found that the Motorola Citrus ranked the least toxic phone followed by the iPhone 4S and the LG Remarq. The new iPhone 5 is ranked fifth, versus its primary competitor, Samsung Galaxy S III, which is ranked ninth.

The most toxic phone tested was the iPhone 2G.

“Even the best phones from our study are still loaded with chemical hazards,” said Jeff Gearhart, research director at the Ecology Centre and founder of HealthyStuff.org.

Every phone sampled in this study contained at least one of following hazardous chemicals: lead, bromine, chlorine, mercury and cadmium. These hazardous substances can pollute throughout a product’s life cycle, including when the minerals are extracted; when they are processed; during phone manufacturing; and at the end of the phone’s useful life. Emissions during disposal and recycling of phones as electronic waste, or “e-waste,” are particularly problematic.

“These chemicals, which are linked to birth defects, impaired learning and other serious health problems, have been found in soils at levels 10 to 100 times higher than background levels at e-waste recycling sites in China. We need better federal regulation of these chemicals, and we need to create incentives for the design of greener consumer electronics.”

A 2004 study found that three-quarters of all mobile phones leach lead at levels that would qualify them as hazardous waste. While tracking e-waste is difficult, it is estimated that 50-80 per cent is exported to countries such as China, India, Pakistan, Vietnam and the Philipines, where there is a labour-intensive, informal recycling infrastructure that often lacks environmental and human health safeguards.

Most of the 36 mobile phones analysed were models released in the last five years. In total, 1,105 samples were analysed for 35 different chemicals and elements. The phones were completely disassembled and interior and exterior components were tested using X-ray Fluorescence (XRF).

“Consumer demand for more sustainable mobile phones is driving companies to produce better products,” said Gearhart. “We also need better federal and international policy to manage both chemicals and e-waste, as well as to promote sustainable design.”