Call it a lesson in workplace etiquette — and policies — and the power of social media.

A Fastenal branch manager in Canada was fired just before New Year’s Day for violating company policy when he lobbed a tweet criticizing the company’s choice of a holiday gift of BBQ sauce and a wooden grill scraper, the CEO confirmed Monday.

“I am not going to deny it. We did terminate an employee,” said Fastenal CEO Dan Florness. He said that Fastenal’s policy about acceptable standards of conduct is given to every employee and posted on the company website.

The tweet, which tagged Fastenal, went viral after at least one news outlet reported it.

When the employee’s critical tweet was discovered, his supervisors reached out to Fastenal’s human resources department to ask what to do.

The recommendation? “Terminate.”

“I was very surprised by the whole thing,” said Florness, who learned of the firing Friday night after a Canadian article and odd messages began appearing on the company website.

Florness called the HR department himself to find out what was going on after some Fastenal customers and web visitors began hurling insults online Friday or saying they would no longer buy construction supplies from Fastenal, which has more than 2,200 locations.

“Calmer heads didn’t prevail over this,” Florness said. “Nobody reached out to me to say, ‘Really? I am getting fired over a tweet?’ It’s an incredibly unfortunate event.”

News of the firing has since gone viral and prompted a backlash on social media, including several website posts and phone messages that were deleted immediately because they were “vulgar” or “threatening,” Florness said during a phone interview Monday.

Florness said the company followed all Canadian termination and severance laws.

Human resource consultants, employer-training groups and the National Labor Relations Board said the issue of disciplining workers over social media violations is not new but it is growing. The issue is definitely something workers should be aware of.

The Society for Human Resource Management (SHRM) advises its member companies to adopt clear warnings in employee manuals about how workers should conduct themselves online and what consequences exist for ignoring policies.

SHRM spokesman Cooper Nye said many corporations are advised to adapt policy wording such as this: “Before creating online content, consider some of the risks and rewards that are involved. Keep in mind that any of your conduct that adversely affects your job performance, the performance of fellow associates or otherwise adversely affects members, customers, suppliers, people who work on behalf of [employer] or [employer’s] legitimate business interests may result in disciplinary action up to and including termination.”

Florness said Fastenal has similar policy language in its employee manual. “It’s standard,” he said.

Asked if Fastenal would consider rehiring the worker, Florness said that while the firing decision may have been “an overreaction” and he may have made a different determination, he was “not going to second guess” his staff. He added that the fired worker was a manager and that HR staffers may have thought he should have known better.

Plus, a lot has transpired in the four days since the firing, including the worker — identified as Hussien Mehaidli, 27, in the CTV News article — giving a phone interview to the outlet.

Florness said reaction was so swift that he made a video and sent it to all his general managers in Canada on Saturday morning to set the record straight. Beyond the facts, he worried that Mehaidli’s tweet hinted that Fastenal’s 22,000 workers in Canada were being treated unfairly.

The barbecue sauce and grill scraper sets Canadian workers received was worth $27 each. While U.S. workers received a different gift, the value of the package was the same. In the past, all workers received the same gift, but customs regulations changed, so operations in the U.S., Canada and Mexico were given a budget and each chose a gift sourced from the respective country.

Mehaidli, who could not be reached for this story, tweeted: “What kind of multi billion company gifts its Canadian employees barbecue sauce as a holiday gift? Yet the USA employees stuff their face with an actual holiday giftbox? @FastenalCompany @FastenalCanada.”

The tweet has since been taken down.