At least three construction workers who are renovating the Smithsonians prized Air and Space Museum in Washington, D.C., have contracted COVID-19 , stirring fears among the workforce that they are risking their health for a project that could wait until the pandemic passes.

The general contractor on the job a joint venture between the construction firms Clark, Smoot, and Consigli informed its subcontractors of the COVID-19 cases in recent days and confirmed them to HuffPost. A fourth worker also received a positive result from a so-called rapid test, and has been asked to undergo a more reliable lab test.

The illnesses have prompted the general contractor to temporarily close portions of the site for deep cleaning, and required workers whove been in close contact with the sick to self-quarantine. A spokesperson said all the workers who contracted the virus were asymptomatic while working, and none of have been onsite since April 30.

One worker on the project, who spoke on the condition of anonymity because employees arent allowed to talk to the press, said the anxiety has led some crews to call out sick rather than risk contracting the virus, with some workers out for days at a time. The majority of his colleagues, he said, believe they should not be working at a time when the U.S. death count due to COVID-19 has surpassed 70,000.

The Smithsonian and construction firms have continued with the years-long revitalization project even though the entire Smithsonian system is closed to the public due to the pandemic.

Were talking about a few months here in a very long project, said the worker. There are 400 working people on this job. Are they willing to risk all their lives and their families lives? Thats a really unnecessary risk in my opinion.

He added, They just dont understand why theyre working in a museum thats shut down to the public.