WASHINGTON -- The high-tech revolution that has made personal computers, cell-phones and "smart" home appliances ubiquitous has also created an ever-growing mountain of toxic "E-waste", the Worldwatch Institute said in a report issued Friday.

"We tend to think of the 'new economy' as being cleaner than the 'smokestack economy'," said Michael Renner, project director for the Vital Signs 2002 Report.

"But manufacturing semiconductors is chemical-intensive. And the short life-span of these products is creating mountains of electronics waste, poisoning groundwater supplies and endangering human health." The electronics industry in 2001 produced 60 million transistors -- the tiny binary switches packed onto microchips -- for every man, woman and child on earth, said the Washington-based environmental think-tank. The chips bearing those vast numbers of transistors are used in products ranging from computers and cars to musical greeting cards.

Demand for high-tech products is growing at breakneck speed as more of the world gets "wired", DPA quoted Worldwatch as saying.

Worldwide mobile phone use doubled every 20 months in the 1990s, and some time this year the total number of mobile phones will exceed the 1 billion existing fixed-line connections, said the report. By 2010, some 1 billion transistors are expected to be made per person, in a process that generates a huge volume of chemical waste.

Making a 15-centimeter silicon wafer produces 14 kilograms of solid waste and thousands of liters of waste water, said the report.

Chip-manufacturing processes require 500 to 1,000 different chemicals.

Other products also carry a high toxic load.

Computer monitors contain up to 3.6 kilograms of lead. Flat-panel screens contain mercury, which can contribute to harming the nervous system.

Cadmium, used in computer batteries, can increase the risk of cancer, harms the reproductive system and can damage developing fetuses, said the report.

In 1997, more than 2.9 million tons of "E-waste" ended up in U.S. landfills, and by 2004, tens of millions of cell phones and an estimated 315 million computers may be headed for American dumps.

California's Santa Clara County, the birthplace of the semiconductor industry, now contains more toxic waste sites than any other county in the United States, said the report.

Worldwide, about 10 per cent of toxic waste is moved across borders, most of it exported from the United States, Germany, Britain, the Netherlands and Australia, often to poor countries.

Half to 80 per cent of used computers, circuit boards and monitors discarded in the United States are sent to China, India and Pakistan for recycling and disposal, exposing workers there to toxins and threatening groundwater supplies, said Worldwatch.

Some countries have taken steps to recycle more of the waste.

Japan has enacted an appliance recycling law that requires consumers to pay manufacturers for the cost of recycling refrigerators, washing machines, air conditioners and, in future, computers.

The European Union is introducing a directive that will place the "cradle-to-grave" burden on manufacturers, in line with mandatory "take-back" programs already implemented by some E.U. member- countries.

The trend is encouraging, said Renner. "Cell phone and computer users," he said, "should be demanding that manufacturers take their products back and design them to be recycled instead of dumped."