HOBART, Australia — Prime Minister Julia Gillard’s proposal for Australia to adopt the second-largest emissions trading scheme in the world, after the European Union’s, cleared its biggest hurdle yet on Wednesday as the lower house of Parliament voted to pass it.

But in a sign of how high emotions continue to run over the contentious bill, scores of angry protesters had to be ejected from a parliamentary viewing gallery after heckling and jeering Ms. Gillard.

The bill, which squeaked through a sharply divided House of Representatives by a vote of 74 to 72, would impose a carbon tax on 500 of the country’s biggest polluters starting in July of next year before transitioning into a market-based trading scheme in 2015. It is expected to easily pass the Senate, the upper house of Parliament, next month with the backing of senators from the Green Party.

“Today is a significant day for Australians and the Australians of the future who want to see a better environment,” the Reuters news agency quoted Ms. Gillard as saying before the vote.