Unite union said 665 workers had refused to accept new terms and conditions.
The company gave employees until 6pm yesterday to accept the plans, which included downgrading of pensions and a freeze on pay and overtime.
Last Wednesday Grangemouth, which provides 85% of Scotland's petrol, was shut down in an escalation of an industrial dispute between Ineos and Unite.
Ineos put forward "a survival plan" for Grangemouth and warned the plant would close in 2017 without fresh investment and changes to workers' terms and conditions.
Unite said that, because of employees' refusal to accept the changes, it expected the owner to "fire up Grangemouth" today.
Ineos sent a letter on Thursday to all 1,350 workers asking them to either reject or accept the plan. The company said about 220 employees had agreed to the new deal.
A spokesman for Ineos last night said the management team would meet today to discuss the vote, and a decision on the plant would be made soon.
"It will take as long as it needs but we'll not sit around for days. The refinery is losing about £2 million a day, so we need to resolve it," he said.
Escalating row
Unite Scottish secretary Pat Rafferty said the "resounding rejection" of the proposals "sends a clear message" to the company owners.
"The people of Grangemouth and Scotland will be expecting [owner] Jim Ratcliffe and the Ineos shareholders to now take heed. Do the right thing tomorrow, drop the threats to the workforce, fire up the plant and get around the table at Acas," said Rafferty. ?
He added: "This is an overwhelming rejection of the company's blackmail and threats. This workforce has said that they want to secure a future for Grangemouth, free from fear, based on negotiation not confrontation."
