The Office of Management and Budget released additional guidance on Jan. 31 outlining how federal agencies are to approach a hiring freeze instituted by the Trump administration.

As expected, the guidance details a list of exemptions, including for military servicemembers, the CIA and the Office of the Director of National Intelligence, as well as essential personnel as determined by government shutdown policy.

Related: Read the guidance

But the guidance also lays out a list of other positions that agencies can hire and other criteria allowing for personnel additions beyond the freeze.

Here are five exemptions from the hiring freeze you might not expect:

The US Postal Service

The USPS’s workforce has seen declines over the last 20 years as part of its goal of cost reductions, falling 29 percent from nearly 875,000 employees in 1995 to almost 618,000 in 2014, according to a 2015 Congressional Research Service report.

USPS employment ticked up to 625,000 in January 2016, and exemptions to the hiring freeze allow it to add more career and non-career positions as needed.

The exemption represents USPS's standing as a public service funded by its own revenues.

NOAA Commissioned Officer Corps

Included in the military exemption is the officer corps of the National Oceanic and Atmospheric Administration, which includes 321 officers tasked with the agency’s numerous scientific operations.

The officer corps was included alongside other uniformed services, including the U.S. Coast Guard and the Commissioned Corps of the U.S. Public Health Service.

Pathways Internship and Presidential Management Fellows

The pair of training and development programs both received exemptions, given the provisional nature of the programs.

Seasonal and temporary employees

The guidance allows for seasonal employee hiring and the maximum term extension for temporary employees. The Office of Personnel Management noted in September 2015that of the more than 2 million federal employees, 144,000 were either seasonal or temporary workers.

OPM director exemptions

The agency’s director can override the freeze for an agency hire if the agency in question can show that the hire:

  • Fills a critical need or is related to essential services.
  • If the role could not be filled by reallocation.
  • If the opening has consequences to operations if not filled in three-to-six months.

The guidance outlines the 90-day executive order that precedes a pending OMB plan to reduce the size of federal government through attrition.