Republican Oklahoma Senator Markwayne Mullin let loose on Teamsters president Sean O’Brien during a heated Senate Health, Education, Labor and Pensions Committee hearing on Wednesday as the two clashed over O’Brien’s salary compared to that of his union members.

The minutes long confrontation began with Mullin, who owns and operates a plumbing business, declaring he was ‘not against unions,’ but also pointing to the intimidation he said he and his employees received from unions when they started being awarded jobs that typically went to union workers.

‘They would show up at my house. They’d be leaning up against my trucks. I’m not afraid of a physical confrontation, in fact sometimes I look forward to it. That’s not my problem. But when you’re doing that to my employees?’ Mullin said. 

‘For what? Because we were paying higher wages? Because we had better benefits, and [weren’t] requiring them to pay your guys’ absorbent salaries?’ he added, before asking O’Brien what he made as a salary.

O’Brien began to answer, but Mullin continued, saying he made $193,000 a year in 2019 while stating the average driver makes $35,000 a year. ‘And what do you bring to the table?’ he then asked O’Brien.

‘That’s inaccurate. State facts. That’s inaccurate,’ O’Brien responded as the two began to talk over each other.

Mullin repeated his statistic on salaries and said, ‘If you don’t know your facts, then maybe you shouldn’t be in your position.’ He then restated his earlier question to O’Brien, asking what he brought to the table for his large salary.

‘What job have you created – one job – other than sucking the paycheck out of somebody else?’ he asked.

‘You’re out of line man,’ O’Brien responded as committee Chair Sen. Bernie Sanders, I-Vt., attempted to stop the back and forth and provide space for O’Brien to respond to Mullin.

The two ignored Sanders and continued talking over each other, appearing to grow increasingly frustrated, before Mullin said, ‘Sir, you need to shut your mouth because you don’t know what you’re talking about.’

‘You’re going to tell me to shut my mouth?’ O’Brien responded, before mocking Mullin’s opening statement in which he said he wasn’t ‘afraid’ of a physical altercation.

Sanders eventually quieted the two and made Mullin provide O’Brien time to speak.

O’Brien, however, continued digging at Mullin, saying, ‘As far as my salary goes – my salary, if you follow me around – I actually looked at this building. I bet you I work more hours than you do. Twice as many hours.’

‘That’s impossible,’ Mullin responded, to which O’Brien said, ‘That’s true.’

‘Sir, you don’t even know what hard work is,’ Mullin said. 

O’Brien went on to claim ‘most’ tractor trailer drivers make over $100,000 a year before the two continued sparring over each other’s salaries and taking personal digs at each other.

After the hearing, Mullin continued to slam O’Brien in a statement to Fox News Digital, also ripping Sanders for not addressing what he called O’Brien’s ‘lack of decorum’ at the hearing.

‘The behavior we saw today was typical of how union bosses, many of whom have never created a single job, use intimidation tactics to pressure employees into joining unions which some workers may deem to be against their interests,’ Mullin said. ‘I find it unacceptable that Chairman Bernie Sanders did nothing to address the lack of decorum from the witness panel.’

‘As a business owner, I’ve seen firsthand how unions have tried to intimidate employees who receive better pay and benefits than unionized workers. Union bosses conveniently ignore the fact that defending the rights of all workers means defending those who do not want to join a union. If union bosses, like those we saw today, reject common sense measures like private ballots and right-to-work, I have a major problem with that,’ he said.

‘This should be simple: American workers and their families should have the freedom to decide what to do with their hard-earned income. As the Senator from Oklahoma, a booming right-to-work state, I will always support workers’ free ability to choose for themselves whether or not to join a union,’ he added.

Fox News Digital reached out to the Teamsters for comment but did not immediately receive a response.

Watch the full video of the altercation here.