Sydney Morning Herald: THE country’s largest oil refiner, Caltex, has stepped up its calls for the Federal Government to quarantine motorists from its proposed carbon-trading scheme, warning it could add an extra $1.4 billion or 10 cents a litre to the nation’s fuel bill each year. In an abrupt U-turn on the 10-cents-a-litre carbon tax the refiner advocated several weeks ago, Caltex yesterday said the Government should "not impose a carbon cost on motorists". With unleaded fuel prices …