Ending “the far left’s energy nightmare” is at the core of his presidency, he said.

The crowd, comprised mostly of men in high-visibility safety vests and work boots, cheered.

The Shell Pennsylvania Petrochemicals Complex will make manufacturing-grade plastic out of liquid natural gas extracted through fracking from the Marcellus Shale deposit.

The facility, a huge web of pipes and half-constructed buildings, is a symbol of Trump’s aggressive pro-fossil fuel agenda — and a powerful statement to his working-class voters that he meant business when he promised to restore the US manufacturing base.

Pennsylvania is a particularly important target: the state will be one of the vital pieces in the 2020 presidential election puzzle and Trump is struggling.

But plastic?

The material, once celebrated as a near-miraculous byproduct of hydrocarbons, is increasingly seen as a scourge, clogging up rivers, circulating forever in the seas, invading the food chain, and showing up everywhere from the deepest ocean to the seemingly pristine Arctic.

All that, Trump says, is someone else’s fault.

“It’s not our plastic. It’s plastics that’s floating over in the ocean,” Trump told reporters on the way to the Shell plant.

“Plastics are fine, but you have to know what to do with them. But other countries are not taking care of their plastic use and they haven’t for a long time.”

Trump’s focus on old-school heavy manufacturing and fossil fuel energy production goes far beyond just visiting the occasional new factory.

He has sought to rewrite strict environmental protection rules that he referred to on Tuesday as 

Trump gleefully told the crowd that his Environmental Protection Agency chief, Andrew Wheeler, “knows how to break it up.”

Breaking it up means the Trump administration’s dismantling of regulations put in place by his predecessor Barack Obama, including the Clean Power Plan, which sought reduced greenhouse gas emissions from power plants.

As he mentioned in his speech, Trump has also pushed to open the Arctic National Wildlife Refuge, a remote and beautiful area of Alaska, to oil drilling.

One of his first acts as president was on an even bigger scale: pulling the United States out of the 2015 Paris Climate Agreement, which aims to unite the planet in a joint push to reduce carbon emissions.

Without US participation, the massively ambitious plan lacks both the world’s biggest economy and most active leader.

But Trump told workers that the restrictions imposed in the agreement would have “taken away our wealth.”

“They didn’t want you to drill. They didn’t want you to frack. They didn’t want you to do steel,” he said. “It wasn’t for us. It was good for others.”

Democrats lining up to take on Trump in 2020 have pushed back vigorously on environmental issues.

Trump knows that many Americans are worried that idealistic environmental campaigners will cost them their factories, their beloved big cars and cheap air travel.

He scoffs at the Democrats’ “Green New Deal” project calling for radical transformation of infrastructure, agriculture and transport to reduce global warming, while also somehow ending income inequality.

But the president can sound no less radical in his opposition to renewables, especially when it comes to his pet hate: windmills.

Wind turbines are described by his own Department of Energy as providing “clean power from an abundant renewable resource.”

But Trump frequently castigates windmills in vehement, factually dubious terms.

On Tuesday, it was no different.

Windmills “destroy everybody’s property values” and “kill all the birds,” he claimed.

He painted a picture of a couple at home losing power during their favourite TV show because the turbines are no longer rotating.

“Darling, I want to watch Donald Trump on television tonight, but the wind stopped blowing and I can’t watch.”

That the scenario was unlikely didn’t matter, because the crowd of builders laughed and Trump had made his point.

Then winding up the story on wind, he ended with the mantra he hopes will power him to reelection next year: “No, we love natural gas.”