MONACA, Pa.: President Donald Trump showcased growing efforts to capitalize on western Pennsylvania's natural gas deposits by turning gas into plastics, as he sought Tuesday to reinvigorate supporters in the manufacturing towns that helped him win the White House in 2016.

Trump arrived in Monaca, about 40 minutes north of Pittsburgh, on Tuesday to tour Shell's soon-to-be completed Pennsylvania Petrochemicals Complex. The facility, which critics claim will become the largest air polluter in western Pennsylvania, is being built in an area hungry for investment.

The focus is part of a continued push by the Trump administration to increase the economy's dependence on fossil fuels in defiance of increasingly urgent warnings about climate change. And it's an embrace of plastic at a time when the world is sounding alarms over its ubiquity and impact.

"This would have never happened without me and us," Trump said, speaking to a crowd of thousands of workers building the site, dressed in fluorescent orange and yellow shirts and vests. In fact, Shell announced its plans to build the complex in 2012, when President Barack Obama was in office.

Trump's appeals to blue-collar workers helped him win Beaver County, where the plant is located, by more than 18 percentage points in 2016, only to have voters turn to Democrats in 2018's midterm elections. In one of a series of defeats that led to Republicans' loss of the House, voters sent Democrat Conor Lamb to Congress after the prosperity promised by Trump's tax cuts failed to materialize.

Today, Beaver County is still struggling to recover from the shuttering of steel plants in the 1980s that surged the unemployment rate to nearly 30%. Former mill towns like Aliquippa have seen their populations shrink, while Pittsburgh has lured major tech companies like Google and Uber, fueling an economic renaissance in a city that reliably votes Democratic.

Trump claimed that his steel and aluminum tariffs have saved the industries and that they are now "thriving," exaggerating the recovery of the steel industry, particularly when it comes to jobs, which have largely followed pace with broader economic growth.

The region's natural gas deposits had been seen, for a time, as its new road to prosperity, with drilling in the Marcellus Shale reservoir transforming Pennsylvania into the nation's No. 2 natural gas state. But drops in the price of oil and gas caused the initial jobs boom from fracking to fizzle, leading companies like Shell to turn instead to plastics and so-called cracker plants — named after the process in which molecules are broken down at high heat, turning fracked ethane gas into one of the precursors for plastic.

The company was given massive tax breaks to build the petrochemicals complex, along with a $10 million site development grant, with local politicians eager to accommodate a multibillion-dollar construction project.