A phone from Sony-Ericsson, a notebook from Sony, and PCs from Dell and Hewlett Packard came top of their categories in a study of green electronics devices  conducted by Greenpeace. There's little cause for celebration, though, as they only scored around half marks, leaving plenty of room for improvement.

Greenpeace published the list to demonstrate that some companies can develop products that do less harm to the environment, and to encourage others to do likewise. The group is particularly concerned about the dangers posed by the 20 million to 50 million tons of electronic waste it says we produce each year.

"We are building an Eiffel Tower of waste every 70 hours," said Zeina Al-Hajj, a spokeswoman for the group.

Worse, no one knows what happens to most of that waste: more than 75 percent of it cannot be traced, according to the environmental lobby group.

"Is it in landfill, or being shipped to China, or sitting in attics? We really have no idea," she said.

Laden with toxic products including lead, beryllium, PVC, phthalates, and brominated fire retardants, poor handling or storage of this waste can damage the environment and human health, the group warned.

To reduce the harm done, the group wants manufacturers to reduce the amount of waste from products, and to make that waste less toxic, by making products that use less energy, choosing environmentally friendly components and materials, making them longer-lasting, and designing products that can easily be recycled.

The Greenpeace study " Searching for green electronics " is a snapshot of some products available on the market between August and November 2007. The group invited PC and phone manufacturers to provide information about their most environmentally friendly notebooks, desktop PCs, mobile phones, PDAs and game consoles. They then evaluated the products on four criteria: use of toxic chemicals, energy efficiency, recyclability and marketing.

Of the companies approached, 14 replied, providing information on 37 products. Some of those contacted, including Acer, Apple, Asus, Microsoft, Nintendo and Sharp, did not respond, or replied too late. This meant that game consoles did not figure in the final report.

The replies were scored, and a weighted total calculated. The highest-scoring device was Sony-Ericsson's T650i phone, with 5.30 out of 10. The other phones submitted scored between 3.6 and 4.4.

In the laptop category, the Sony Vaio TZ11 led with 5.29 points out of 10. Other products listed scored between 3.49 and 4.82.

None of the desktop PCs submitted scored more than half marks: front runners were the Dell Optiplex 755 and the Hewlett-Packard dc5750, with 4.71 points each.

The Greenpeace is not a consumer guide said Yannick Vicaire, one of its authors, although it does show the questions that buyers should ask of manufacturers.

The report should be seen as a comment on the devices studied, and not on the brands as a whole, said Al-Hajj.