ONLY A FIFTH of biofuels in UK vehicle tanks meet environmental standards, according to the first quarterly report on the fuel.
The Renewable Fuels Agency (RFA) figures also included the first breakdown of how individual companies were doing on delivering carbon savings and preventing problems such as deforestation and pollution.
They showed several major firms, including BP and Esso, had not yet reported any of their products as meeting the fledgling environmental standards.
The Government has set a goal for 30% of biofuels to meet the environmental levels over the first year of the scheme.
According to the report, it was better news for carbon savings delivered by biofuels in the first three months after the requirement came into force in April for them to make up 2.5% of transport fuels.
The RFA said most companies met or came close to the current target to deliver carbon savings of 40%.
But several companies, including Esso, had failed to meet the three Government targets for carbon savings, the amount of fuels meeting environmental standards or reporting on the origin and type of raw material used.
Just 5% of biofuels were reported as coming from the UK, but 97% of those were classified as meeting environmental goals.
The Renewable Energy Association's head of transport biofuels Clare Wenner said the report "clearly shows that the UK biofuels industry is delivering on its promises to provide biofuels that make greenhouse gas savings and are produced in a sustainable way".
But with the origin of almost a quarter (23%) of biofuels unknown and the vast majority imported, environmental groups raised new concerns about their sustainability.
Environmental group Greenpeace said the figures showed how weak and confused Government policies were allowing companies to boost profits and supply cheaper biofuels such palm oil, which has been linked to deforestation in South East Asia.
Greenpeace chief scientist Dr Doug Parr said the report would make "grim reading" for the new Transport Secretary Geoff Hoon.
He said: "It's time the Prime Minister stepped in and scrapped these compulsory targets for biofuels because without safeguards in place they are quite clearly a disaster for the world's forests and a major obstacle in the fight against climate change."