CHICAGO (CBS Chicago/CBS News) — The U.S. Supreme Court has had its say on the reach of two COVID-19 vaccine mandates from the Biden administration.

The Supreme Court on Thursday blocked the administration’s vaccine-or-test rule for businesses with at least 100 workers, but granted a separate request from the Biden administration to allow its vaccine mandate for health care workers to take effect.

READ MORE: Bears Hire Colts Defensive Coordinator Matt Eberflus As New Head Coach

In an unsigned opinion on the rule from the Occupational Safety and Health Administration (OSHA), which would require workers to be vaccinated against COVID-19 or submit to weekly tests, the high court said a slew of GOP-led states, businesses and nonprofit organizations that challenged it are “likely to prevail.”

“Although Congress has indisputably given OSHA the power to regulate occupational dangers, it has not given that agency the power to regulate public health more broadly,” the court said. “Requiring the vaccination of 84 million Americans, selected simply because they work for employers with more than 100 employees, certainly falls in the latter category.”

The three members of the court’s liberal wing — Justices Stephen Breyer, Sonia Sotomayor, and Elena Kagan — dissented.

So what does this mean for you and your workplace? CBS 2’s Marie Saavedra asked a legal expert to break down the court’s ruling.

Inside the hallowed halls of the Supreme Court came that decision that requiring COVID vaccines or testing at many workplaces cannot be a decision made by the president.

“They’re not able to affect 84 million Americans at the stroke of a pen,” said Chicago-Kent College of Law Professor Harold Krent.

It came from legal challenges to the president’s announcement that by Jan. 4, businesses with 100 employees or more would require workers to be vaccinated or take weekly tests. Enforcement would be up to OSHA.

“And if they can regulate exposure to toxins in the workplace and benzene, why not shouldn’t they try to help prevent some kind of illness through COVID?” Krent said. “But to the court, that was just a step too far.”

The court, again, ruled that OSHA doesn’t have that reach. Still, legislatures, states, and private businesses can make and enforce their own vaccine requirements.

The Biden administration hopes they do.

READ MORE: Pair Charged In Murder Of 8-Year-Old Melissa Ortega Denied Bail; Accused Teen Gunman Committed Three Previous Carjackings, Prosecutors Say

“In this pandemic, it is up to individual employers to determine whether their workplaces will be safe for employees – and whether their businesses will be safe for consumers,” said White House Press Secretary Jen Psaki.

So it is likely that many workplaces won’t see their current vaccine or test rules change.

“There will still be many employers that do require vaccines and/or testing – just not at the federal level,” Krent said.

The high court, though, gave the green light to a requirement that health care workers in facilities that receive Medicare and Medicaid funding must be vaccinated, siding 5-4 with the Biden administration.

“The challenges posed by a global pandemic do not allow a federal agency to exercise power that Congress has not conferred upon it,” the Supreme Court said in its second unsigned opinion. “At the same time, such unprecedented circumstances provide no grounds for limiting the exercise of authorities the agency has long been recognized to have.”

Justices Clarence Thomas, Samuel Alito, Neil Gorsuch, and Amy Coney Barrett dissented.

The decisions come less than a week after the justices heard oral arguments on the emergency requests regarding the vaccine-or-test rule and vaccine requirement for health care workers.

President Biden first announced the rules in September as part of a broader strategy from his administration to combat the spread of the Delta variant, which drove a surge of infections toward the end of the summer.

But the nation is now battling another spike in COVID-19 infections and hospitalizations from the highly transmissible Omicron variant, and the Biden administration has said its vaccine requirements are crucial for protecting workers and patients.

The Supreme Court was asked to intervene last month and swiftly held oral arguments to weigh the emergency requests.

MORE NEWS: Chicago Weather Alert: Winter Storm Watch On The Way

CBS News’ Melissa Quinn contributed to this report.

Marie Saavedra