By Jonathan Fildes
Science and technology reporter, BBC News
Nintendo says it did not take part in the Greenpeace survey
Games firm Nintendo has come bottom of a ranking of the world's most eco-friendly electronics firms.
The quarterly Greenpeace Guide to Greener Electronics ranks 18 electronics firms by how green their production processes and products are.
In the latest guide most firms have seen their ranking plummet as the charity introduced new, stricter guidelines for evaluating companies.
Nintendo said its scored low because it had not provided data for the survey.
"Greenpeace chose to conduct a survey and produce a report, which graded companies upon the voluntary submission of information," the firm said in a statement.
"Nintendo decided not to take part in the survey and were therefore 'ungraded' in the resulting report.
But Greenpeace countered the company's statement and insisted it had been graded.
"There is no choice," Iza Kruszewska, toxics campaigner for Greenpeace, told BBC News.
She said the campaign group had regularly contacted the games firm since 2007 but had not had any response. In the end it had been forced to use information from Nintendo's website, she said.
""They've decided not to engage," she said.
The guide was first started in August 2006 and is now in its eighth edition.
Microsoft were second from bottom in the latest list
It ranks the top market leaders of the mobile phone, computer, TV and games console markets according to their policies and practices on toxic chemicals and recycling.
The organisation said that the guide has already led to a reduction in the amount of toxic chemicals being used in the electronics industry.
"We know that brands are putting pressure on their suppliers to meet our commitments," said Ms Kruszewska.
The latest guide also includes new stricter guidelines.
"For this edition we tightened the e-waste and chemical criteria and we also added a new energy requirement," said Ms Kruszewska.
The new energy guidelines score a company for disclosing their greenhouse gas emissions, their commitment to absolute cuts in their own emissions and support for mandatory global emissions reductions.
In particular, Greenpeace has asked companies to state support for a "strong post Kyoto agreement" on their international websites.
"We see companies scoring zero on all energy criteria," added Ms Kruszewska.
"Clearly it is going to take companies some time to improve on our demands,"
The latest guide also assessed the energy efficiency of a selection of each company's products to see if they meet or exceed the US Environmental Protection Agency's Energy Star rating.
This sets minimum standards for energy efficiency for many types of electronic products.
"Not only should all their products meet these standards, but 30% should exceed it to score full marks," said Ms Kruszewska.
In the latest version Sony and Sony Ericsson were the only companies to score more than five out of 10.
Nintendo came bottom of the list with a score of less than one.
Earlier this year, Nintendo was criticised by Greenpeace for its "non-existent" environmental policy.
Microsoft came second from bottom; a position that reflected its "low score on climate criteria".
A spokesperson for the firm said: "Microsoft is committed to environmental sustainability and has many programs and policies in place to lessen our footprint.
"In our consumer electronics business, we comply with and exceed all environmental guidelines and regulations.
We are committed to making ongoing progress on environmental issues while maintaining product durability, safety and performance."