Congress has agreed to let California set new air pollution standards on small, off-road engines while requiring federal regulators to adopt a nationwide emissions reduction plan for the rest of the US by 2005.

It is thought that the final draft of the bill will now go through in a $390 billion spending bill that is set to complete Congress' work for the year.

Under California's new proposals, even small engines such as power lawn mowers and leaf blowers will require a catalytic converter.

The compromise settled on between some fierce opponents in Congress and those seeking stricter emissions, will allow California to continue in its new emissions rules but require that the EPA considers safety issues when offering final approval.

Some opponents of the bill had warned that catalytic converters could be deemed dangerous due to their extreme heat, but the news is likely to see an increase in the number of devices used in the US.

Under the rules the agency would also be required to propose a new, nationwide emissions standard for off-road engines smaller than 50 horsepower by the end of next year, with adoption scheduled for 2005.

That rule will then become the standard law for any state without rules specifically governing such applications.