WASHINGTON (CN) – With no movement on Trump’s $5 billion demand for border-wall funding, federal employees, and even more federal contractors, are starting to feel the impact of the partial government shutdown as the workforce heads into 2019.

Smaller national parks like Fort McHenry National Monument in Maryland, and state and local farm service centers through the Department of Agriculture, were among those that closed their doors indefinitely as lawmakers failed to pass a temporary spending bill Friday night.

But as the U.S. workforce picked back up Wednesday morning after the Christmas holiday, additional operations either went dark or are beginning to see employees work without payment.

Those include about 89 percent of the Food Safety and Inspection Service under the U.S. Department of Agriculture and about 8,000 employees at the Department of Health and Human Services.

Scientific sections of the government, from those at NASA to the U.S. Geological Survey and beyond, will see about 380,000 employees furloughed while another 420,000 “essential” employees, like air-traffic controllers and and those who manage lab animals, would return to work without pay.

By Wednesday morning several heads of agencies took to Twitter to clarify the extent of the partial shutdown’s impact on their workforces while reassuring the public that their broader work would not be overly impacted.

Among them was Scott Gottlieb, head of the U.S. Food and Drug Administration.

“During this partial government shutdown, the FDA is able to continue activities involving the safety of human life,” Gottlieb wrote. “ As such, we continue important work related to the importation of products we regulate.”

According to the Department of Health and Human Services, about 41 percent of their staff would be furloughed as of Wednesday.

And while agencies are continuing to develop plans for employees, it is harder to narrow the impact faced by those government contractors who work for those impacted agencies. Contractors face a different challenge because private companies continue to be bound by labor laws, while the government can manipulate labor laws to keep things moving.

In a post on the National Law Review website, they detailed the complex nature of this issue. Things like the Worker Adjustment and Retraining Notification, or WARN Act, require 60 days notice of a work stoppage and the sudden nature of this shutdown could cause them to run afoul of that law.

They suggested telling employees not to work at all if their federally linked agency is furloughed, or have them work a reduced work week.

“A government shutdown would require many government contractors to make difficult choices,” wrote Guy Brenner, a partner in the Labor & Employment Law Department.