Dell has won praise from environmental group Greenpeace for becoming the latest company to promise to remove the worst toxic chemicals from its computing products.

The move closely follows a similar pledge from rival HP. Greenpeace said that both companies have bowed to pressure from activists to make their products greener and help tackle the growing mountain of toxic waste.

Dell promised to phase out the use of two key groups of chemicals known to be hazardous to the environment - brominated flame retardants and polyvinyl chloride - by 2009.

According to Greenpeace, HP, LG Electronics, Nokia, Samsung, Sony and Sony Ericsson have already made commitments to eliminate the use of some hazardous chemicals in the near future.

But a number of other companies, including Acer, Apple, Fujitsu-Siemens, IBM, Lenovo, Panasonic, Siemens and Toshiba, have so far failed to commit. Motorola recently broke its promise to clean up, the organisation said.

A recent survey across nine countries by Ipsos MORI revealed that most people would pay extra for a more environmentally friendly computer, and that companies should be held responsible for dealing with hazardous waste from PCs.

The survey, carried out earlier this year, found that computer users would be prepared to pay a premium ranging from $59 in Germany, $118 in the UK, $199 in China and a whopping $229 in Mexico.

There is evidence to suggest that hundreds of thousands of old computers and mobile phones containing toxic chemicals are dumped in landfills or burned in smelters every year.

Thousands more are exported to Asia, often illegally, from the Europe, US, Japan and other industrialised countries.