The report, "Green Electronics: the search continues," evaluated 50 products from 15 companies, identified by the manufacturers as their most environmentally friendly models, but found that none of them performed well against all criteria. Greenpeace will hold a news conference at the International Consumer Electronics Show in Las Vegas on Friday to discuss the report's details.

In its tests, Greenpeace found that fewer of the products contained PVC (polyvinyl chloride) plastic and other hazardous chemicals than those tested a year ago. In the past, it has campaigned vigorously against the use of toxic materials in products.

One thing that changed for the better in 2008 was the increasing use of LED (light emitting diode) displays, which avoid the use of backlights containing mercury, and are also more energy efficient, Greenpeace said. Companies are also using recycled materials, for example in TV and monitor casings, and are increasing the volume of old products that they take back for recycling.

Despite all these improvements, the best-rated product, Lenovo's L2440x computer monitor, only scored 6.9 out of 10. The second-placed product was also a monitor, Fujitsu Siemens Computers' ScenicView P22W-5 Eco, with 6.33.

Lenovo's weakest link was energy use. It lost points for not tracking the energy used to manufacture the monitor, and could have done better by providing more information about the monitor's energy-saving mode. It could have scored an easy point by fitting a real off switch that physically cuts all current. Instead, like many devices, it has a standby switch that contributes to so-called "phantom" power consumption by maintaining power to some of its circuitry even when it is apparently turned off.

Lenovo also lost marks for exploiting exemptions in the European Union directive on the reduction of hazardous substances (RoHS), which allows companies to continue using banned toxic chemicals in their products in certain circumstances.

Other companies have shown that they can do better in the categories where Lenovo fell down. If a manufacturer were to follow the best practices of any of the companies seen by Greenpeace in each category (energy use, reduction of toxic chemicals, recycling and so on), then it would score 8.6 out of 10.

Lenovo was also the top scorer in the desktop computer category -- although that business unit clearly still has much to learn from the monitor division, as its ThinkCenter 58/M58p only scored 5.88 out of 10, narrowly beating Fujitsu Siemens Computers' Esprimo E7935 E-Star 4, which scored 5.73.