Workers at a new Shell plant in Pennsylvania say were told they had to attend a speech by President Donald Trump in order to get paid, according to a report from the Pittsburgh Post-Gazette.

Workers were also told "no yelling, shouting, protesting or anything viewed as resistance will be tolerated at the event. An underlying theme of the event is to promote good will from the unions. Your building trades leaders and jobs stewards have agreed to this."

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Trump's booming voice filled the confines of the new Shell Pennsylvania Petrochemicals Complex in Western Pennsylvania on Tuesday as the crowd, consisting of mostly male construction workers in orange and yellow construction vests, listened attentively.

The president's rally-style speech, which a senior administration official described as "not a political event but an official event," included jabs at Sen. Elizabeth Warren and former Vice President Joe Biden, calls for union leaders to support him in 2020, a warning that Democrats would take their jobs, and taking credit for the complex, which is still under construction and was first announced in 2012 when former president Barack Obama was still in office.

In addition to the ethical concerns of the speech, which was expected to focus on energy but instead transformed into a full-on campaign rally (despite being funded by taxpayer dollars, which are not supposed to go toward political campaigns), the Pittsburgh Post-Gazette on Friday revealed another red flag: the workers in the crowd didn't attend Trump's event by choice; rather, they had to attend in order to get their paychecks.

While attendance was not mandatory, union workers who didn't show up had to forfeit their pay, similar to if they had opted to skip work for the day, according to the Post-Gazette. One contractor, referencing a memo sent to union leaders by Shell, told employees that they would only be paid if they showed up at 7 a.m., scanned their ID cards, and prepared to stand for hours through lunch. "No scan, no pay," they were told.

Workers were also told "no yelling, shouting, protesting or anything viewed as resistance will be tolerated at the event. An underlying theme of the event is to promote good will from the unions. Your building trades leaders and jobs stewards have agreed to this," the newspaper reported.

An anonymous union leader told the Post-Gazette that one day of work could amount to around $700 in pay, benefits, and a per diem payment for out-of-town workers. Other union leaders added that they were not consulted about the arrangement in advance.

MONACA, PA - AUGUST 13: Over 5000 union contractors wait to listen to US President Donald Trump speak to at Shell Chemicals Petrochemical Complex on August 13, 2019 in Monaca, Pennsylvania. Photo by Jeff Swensen/Getty Images

Shell spokesperson Curtis Smith told Business Insider that "Tuesday was treated as a training (work) day with a guest speaker who happened to be the President. We do these several times a year with various speakers. The morning session (7-10 AM) included safety training and other work-related activities."

"It was understood some would choose not to attend the Presidential visit and take paid time off (PTO), instead," Smith added. However, the company told the Post-Gazette that those who opted not to attend would have an excused, but non-paid, absence. When asked for clarification on those conflicting statements, Smith told Business Insider, "yes, that was also an option."

Business Insider then questioned Smith as to why workers would opt to take an excused but non-paid absence over PTO. "PTO comes from a personal account of accrued hours," Smith said.

Smith told Business Insider that on-site workers have a 56-hour workweek, which provides for 16 hours of overtime. As such, workers who didn't attend Trump's speech and took the PTO would not be eligible to receive that overtime and would be paid at the regular rate. In comparison, workers who did attend the speech and showed up for work later in the week would be paid at a rate of time and a half.

As noted by the Post-Gazette, this is "despite the fact that both groups did not do work on the site Tuesday."

Ken Broadbent, a business manager for Steamfitters Local 449, told the Post-Gazette, "this is just what Shell wanted to do and we went along with it." He said that workers who didn't want to show up for work that day were free to do so because "this is America."

The $6 billion plant, located outside of Pittsburgh, is scheduled to be finished in early 2020 and will focus on producing plastic from ethane, a natural gas byproduct created during fracking.