SeaTac’s closely watched election over a $15-an-hour minimum wage at airport-related businesses will be watched much more closely the next few days.

Proposition 1’s election-night lead of 261 votes largely disappeared by Friday, reduced to a mere 43 votes.

The election became a nail-biter as the yes side’s initial 9 percentage-point lead shrank to under 1 percent: 50.43 yes to 49.57 percent.

“The declaration of victory was premature,” said Don Stark, spokesman for the business-backed Common Sense SeaTac campaign against the minimum wage.

With the next count scheduled for Tuesday, the day after Veterans Day, Stark said the outcome remains uncertain.

“As we’ve said from the beginning, we’re cautiously optimistic and it looks like there was good reason to be that (cautiously optimistic) on Tuesday night. We’re obviously going to watch the returns carefully.”

Heather Weiner, spokeswoman for pro-Proposition 1 organization Yes! for SeaTac, said, “We are surprised by the numbers but we’re not pessimistic. We are still optimistic that the final outcome will be yes and approval of Prop. 1.

“We do know that a lot of people who told us they were voting yes voted late.”

If approved, the proposition would raise the wage floor to $15 an hour and guarantee paid sick leave for about 6,300 hospitality and transportation workers.

The tightening election was a remarkable turnaround from the yes side’s euphoria on Election Night.

On Wednesday, David Rolf, president of Service Employees International Union Healthcare 775 NW — a key backer of Proposition 1 — said the union would work with Seattle Mayor-elect Ed Murray to advance a $15 minimum wage there.

Hundreds of ballots — around 700 — remain to be counted for the city that surrounds Seattle-Tacoma International Airport, the campaigns said.

King County Elections reported receiving 6,119 mail ballots from SeaTac’s 12,108 registered voters through Friday night.

State law provides no automatic recount for local ballot measures.

However, a campaign can request a recount but must pay the cost.

Keith Ervin: 206-464-2105 or kervin@seattletimes.com