A new Irish company has applied for a listing on the US Nasdaq stock exchange to finance the global marketing of an oil filter which could greatly reduce crude oil production costs. Mr Roger Duffield, chief executive of Klinair Environmental Technologies, said that he was in discussions with five major oil companies on use of the filter which, he says, "cleans" crude and unrefined oils of their sulphur and heavy metal contents, leading to significant health benefits if field tests are successful.

"We have signed confidentiality agreements for development of the technology for specific applications," he said. The current method of removing sulphur from petroleum is not fully effective, and requires temperatures of 371 degrees Celsius at 70 times atmospheric pressure.

"If you look at conventional oil recovery and refinery, the industry has not changed for maybe 50 years," he said.

His project has received backing from the Centre for Marine and Petroleum Technology (CMPT) in Britain, a non-profit company part-funded by the oil industry to develop new technologies.

"We believe that we are now at a stage where the potential is so good that we need to take it out of the lab and into a field test," said Mr Roger Lane-Nott, CMPT chief executive.

Mr Neasan O'Shea, chief technical adviser at Irish Refining in Whitegate, Co Cork, said that a process which could desulphurise diesel oil for cheaper than $5 a tonne would make a big impact on the world's daily usage of 65 million barrels of oil.

"If it comes off, it would be quite a breakthrough. There is a lot of work to be done.

"When they have developed it to a particular point, we will give them help in testing it out", he said. Mr Duffield, a resident of the Cayman Islands where Klinair is registered, said that a development programme was continuing at the University of Limerick, which specialises in this area of inorganic chemistry.

The company is having its listing organised by its financial advisers, BDO Simpson Xavier, and expects to be on the Nasdaq next month. It plans to manufacture the device in Shannon, Co Clare, next year, employing up to 500 people.

"This is another Microsoft in its embryo stage. This is going to revitalise the oil and gas industry," he said.

Mr Duffield, a former investment banker, has worked on the project for over seven years and took out international patents on the intermetallic process in Ireland, where royalty income is tax free.

"My main motivation was that I always felt that somebody somewhere had to do something about creating an environmental company that would have some impact on the world."