(CNN) — Days before the July 4 holiday weekend, the main security checkpoint at Hartsfield-Jackson Atlanta International Airport -- the world's busiest airport -- has been closed for cleaning after an employee there tested positive for the coronavirus, according to the Transportation Security Administration.
TSA Spokesman Mark Howell said the Domestic Main checkpoint has reopened a few lanes as of Wednesday evening, but will "likely not fully open until tomorrow," following a deep clean.
All passengers are currently being screened at a smaller checkpoint, T North. Another smaller checkpoint at the airport, T South, has been closed due to a construction project.
Howell said the situation is causing longer lines than usual at the T North checkpoint.
Because the checkpoint is expected to reopen by Thursday, the situation is not expected to impact holiday travelers this weekend.
Howell said TSA expects to screen about 27,000 people at the airport on Thursday and Friday, which is about 50% more than it has seen recently. The agency is bringing in more employees to work over the holiday weekend because of the higher volumes.
More than 860 TSA employees nationwide have tested positive for the coronavirus, including at least 29 at Atlanta's airport -- 28 of whom are screeners.