Car makers will soon be responsible for recycling their vehicles when they are scrapped, but increasing levels of plastics and composites could cause problems.

This week, after some delay, the DTI introduced legislation making vehicle manufacturers and professional importers responsible for recycling their cars and light vans when they are scrapped.

The regulations, due to come into force on 3 March, complete the UK's implementation of the EU-led End of Life Vehicle (ELV) Producer Responsibility Regulations. Under the legislation, from 2006, 85 per cent of the weight of all cars and small vans will need to be re-used, recycled or recovered at the end of the life of the vehicle. This percentage will rise to 95 per cent from 2015.

For the first year, as usual, the final owner of the car will have responsibility for disposing of their vehicle. However, after 1 January 2007, manufacturers and importers will be required toprovide free take-back of vehicles through a national network of authorised treatment facilities.

Albeit in two years' time, the legislation should end the UK's current problem with abandoned vehicles — every two minutes someone in the country dumps their car at the side of the road rather than paying councils or scrapyards around £40-£50 for the privilege of removing it.

Around two million vehicles are scrapped in the UK every year, with roughly 1.2 million of these going to vehicle dismantlers while the remainder go direct to scrapyards.

Though the majority of cars are metal, roughly 20 per cent of a vehicle consists of its tyres, materials such as oil and antifreeze, and an increasing amount of plastic, used in areas such as fascias and bumpers.

Under the ELV directive, these materials are classified as environmental hazards and must be removed for safe disposal. Since February 2004, when recyclers had to meet minimum standards by investing in technologies and gaining licences to operate under the new rules, around a third have closed down, many claiming that the cost of complying as well as covering the £50 that it takes to dispose of hazardous materials in each vehicle makes operation commercially impossible.

While in the short term there has been evidence that the dumping of vehicles has increased, manufacturers have had plenty of warning about the directive and few foresee more than teething troubles complying with its demands. They are due to provide the government with Producer Plans detailing arrangements for recycling their ELVs by 1 July, ensuring that sufficient capacity is in place by the time the regulations are enforced.

Both Peugeot-Citroen and Ford confirmed that they are planning to comply with the regulation through contracts with recycling service providers.

Increasing amounts of metallic waste are able to be recovered during the disposal process. Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO)'s Minerals Division recently announced the development of a cheap jig method to separate up to 33kg of steel and 3kg of copper from every tonne of dry sludge produced when vehicles are shredded.

The system combines magnetic separation to take out the steel with hydraulic classification, a process in which particles of the same specific gravity are separated by backwashing with water. The smallest particles tend to rise to the top of the bed, and the largest particles sink to the bottom owing to variations in weight-to-surface area ratios.

Finally, a process of gravity concentration is used, in which the machine's movement separates the materials, as heavier particles settle faster than light ones.

However, pressure on manufacturers to produce cars with higher fuel efficiencies has led to the design of lighter vehicles with increasing levels of plastics and composites. This could create problems for car makers in complying with the ELV rules, particularly as the legislation grows more demanding over time.

'At the moment, sorting the plastics used, particularly for car interiors, is a very difficult job,' said Nick Matthews, principal fellow of the Warwick Manufacturing Group, part of the University of Warwick. 'It's hard for the average scrapyard employee to sort them - many parts weigh less than 200g so they're hard to find. Unless something is done, it may be increasingly difficult for manufacturers to continue to use them. Car makers must start to design for disassembly and make different plastics easy to distinguish.'

Thermosetting composites pose another problem. These plastics are commonly used to make light yet strong spoilers, bonnets and body panels. However, they cannot be melted down at the end of their life. A consortium led by the recycling specialist SIMS Group has recently been awarded an £880,000 grant from the DTI aimed at developing a method for recycling the materials, particularly sheet and bulk mould compounds.

'The only thing that can be done with them at the moment is to put them in landfill,' said Dr Luke Savage, project generation manager at consortium members Exeter Advanced Technologies (X-AT), based within the School of Engineering and Computer Science at the University of Exeter.

X-AT's research has shown that when ground up, the plastics can be re-added to the same resin, producing a material with enhanced mechanical properties. 'The resulting materials are good for products such as underground cable housing where appearance does not matter. Another option is using the regrind in brake pads. No-one wants to pay a great deal for them and they already contain fibre and cured resins.'

However, there are question marks over whether such recycling is the best option in the long term. 'Recycling is very energy intensive,' said Warwick's Matthews. 'We are therefore looking at the use of sustainable materials rather than recyclable ones. If plastics are not made from petrochemicals they can be put in landfill and composted down.'

A spokesman for Peugeot-Citroen said that even if scrap prices were to fall, the company still expects the cost of removing polluting substances from the vehicle to be offset by the value of the materials recovered. But Matthews questions whether manufacturers will find it as easy to cover the cost of the process as they do at present.

'Scrap steel is currently very valuable owing to the demand from China in particular,' he said. 'A few years ago, though, the industry was going belly up. The price may plunge again, so car makers must protect themselves against thinking that covering the cost of recycling by selling on is an easy option.'

Unless there is money to be made from old bangers, the consumer may end up paying the price for a cleaner environment through a more expensive and perhaps even less fuel-efficient car.