Mercer County, Pa. - While President Trump's economy is benefiting tech and energy sectors, the manufacturing slump in the Rust Belt regions could test whether he can continue to appeal to blue-collar workers this November.

In the valley, some of the campaign promises and changes to U.S. trade deals might be resonating on the production lines at some local steel plants.

"I think our administration has done a good job of trying to get people back to work," William Thomas III said, president of Colonial Steel Products, Inc. 

Thomas says the workforce is the one thing he looks at to gauge how the economy is faring. The plant in West Middlesex, Pennsylvania, is hiring. The global sourcing company has experienced growth over the past three years.

Without getting political, he hopes that the changes to trade deals stay put.

"Depending on the outcome of the election, I think it would be extremely foolish for somebody to just change overnight with the stroke of a pen and eliminate it, you have to look at what the impact is to the domestic companies if you were to just take it away," Thomas said.

The Trump administration recently expanded tariffs on steel and aluminum products to include smaller parts that go into some automobiles and tractors.

While Mexico and Canada are among the countries that have tariff exemptions, other countries, including China, do not.

As long as the steel tariffs are in place, the company that operates Sharon and Wheatland Tube is giving its workers $1,000 bonuses annually.

Zekelman Industries operates those plants and many more across the country. The company hired more than 700 workers across the U.S. over the past four years and has plans to hire many more. The company is now hiring at its Mercer County facilities.

"Ever since Donald Trump was elected, we've seen an increase in order intake, in the confidence of all our customers-- I kind of like to refer to it as just a bounce in everyone's step, we've seen real steady growth," Mickey McNamara said, executive vice president of Zekelman Industries.

McNamara says some of the older plants in the country might disappear as the market in the U.S. evolves. Overall, he can't imagine why Trump's appeal wouldn't be stronger in 2020 compared to 2016.

Not every plant is experiencing positive results under Trump's tariffs.

NLMK in Mercer County saw layoffs in December.

"Where the policies in Washington are hurting us are with the steel industries that have stuck around Mercer County, like NLMK, for example," Randy Seitz said, president and CEO of the Penn-Northwest Development Corp.

NLMK imports its raw materials from overseas. The tried and failed to get a tariff exemption from the Trump administration. The company is known for offering strong wages and benefits.

"The tariff could be driving them out of business, so there could be 700 people out of work because of that policy," Seitz said.

The U.S. Department of Labor reports that manufacturing jobs in the valley make up the largest group of workers at 20-percent of the workforce.