The Biden administration is trying to figure out how to enforce its nationwide COVID-19 vaccine mandate amid challenges already posed by workers at companies that have pursued their own requirements.

The Occupational Safety and Health Administration is working on a draft rule requiring all companies with more than 100 employees to mandate vaccines or weekly COVID-19 tests as conditions of employment, NBC News reported Monday.

President Joe Biden announced the mandate early last month, but employees with airlines, healthcare services, and law enforcement face potential termination ahead of deadlines, the Washington Examiner said.

The airlines industry, affected by staffing shortages during the pandemic, is bracing for more delays and canceled flights driven by employee departures related to vaccine mandates.

A Southwest Airlines pilots union representative on Monday denied that a massive amount of delayed and canceled weekend flights was due to pilots protesting a looming mandate at the company by calling out sick.

United Airlines began firing nearly 600 employees in early October, when its vaccination mandate went into effect.

In the healthcare industry, some companies scurried to accommodate firings and potential firings of staff who refuse to take their COVID shots.

Gov. Kathy Hochul, D-N.Y., prepared an emergency plan for dealing with healthcare worker shortages as the state's Friday vaccine mandate deadline approached.

Up to 50,000 New York hospital employees remained unvaccinated as of Oct. 6, according to state data.

One hospital system in Erie County, New York, which includes Buffalo, suspended inpatient elective surgeries and almost all ICU transfers as it prepared for likely staff shortages, the Examiner said.

Companies that violate Biden's vaccine mandate could face fines of nearly $14,000 per violation, according to administration officials, though enforcing a national vaccine mandate could be much more difficult.

OSHA had 862 inspectors for the country as of last year, according to data obtained through a Freedom of Information Act request by NBC News. This year, despite new hires, the agency lost another 65 inspectors, according to data obtained from OSHA.

And OSHA training takes time. David Michaels, who ran the agency for seven years, told NBC News he doesn’t "think those new inspectors will be out in the field anytime soon."

Many small companies also want the government to pick up the cost for testing employees who choose not to get vaccinated. The Biden administration, however, has not indicated whether it will pick up the tab. If not, the cost could be passed on to workers.

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