SAN FRANCISCO, Nov. 6 (Xinhua) -- Voters in the U.S. state of Washington on the west coast Tuesday voted down a proposal that advocated imposing carbon tax on companies using fossil fuels, a local radio reported.

KUOW, a Washington-based radio station in Seattle, said the voters have rejected the ballot initiative that would have levied a fee of 15 U.S. dollars per ton on certain carbon emissions beginning in 2020.

As of Tuesday evening, 56.3 percent of the voters opposed the initiative as more than 1.9 million ballots from all 39 counties in the state have been tallied.

The results dealt a big blow to the state's efforts to cut Washington greenhouse-gas emissions, because the initiative, if passed, would have raised more than 1 billion dollars annually by 2023.

The battle over Washington's carbon tax has received high-profile attention both at home and abroad as both supporters and opponents spent tens of million dollars in getting the votes in their favor.

Supporters including Washington State Governor Jay Inslee, Attorney General Bob Ferguson and Microsoft co-founder Bill Gates have all expressed their resolve to back the initiative. They spent at least 12 million dollars on the battle.

Opponents such as the oil industry raised more than 25 million dollars to quash the proposal, arguing that the tax could have cost an average household over 400 dollars in the first year.

This is the second time that Washington voters have opposed hiking prices on fossil fuels. They rejected a similar carbon tax in 2016.