To appear on the ballot, Initiative 841 needed 197,734 valid signatures from registered voters. The measure's backers - the Building Industry Association of Washington - handed in 258,411 signatures, enough to virtually guarantee it would qualify.

State officials estimated 206,608 are valid, based on random sample check of 12,666 signatures.

The initiative would immediately repeal the ergonomics rules issued by state Department of Labor and Industries in 2000. The association, the political branch of the state's homebuilders spent more than $350,000 - nearly all for signature-gathering - to put Initiative 841 on the ballot, according to AP.

Labor unions and state officials including Gov. Gary Locke argue the rules would avert thousands of painful injuries as well as millions of dollars in lost wages and productivity.

Labor groups, most notably the Washington State Labor Council, are gearing up to fight the initiative.