Suburban Hospital's emergency department shut its doors to ambulances on Monday, Sept. 7, after a technology failure knocked out systems at three Johns Hopkins hospitals across the region.

The Bethesda hospital was placed under "Code Black" status, a designation Maryland reserves for emergency departments effectively closed to EMS traffic because of unsafe conditions such as utility failures or fires, according to the Maryland Emergency Department Advisory System. Under Code Black, ambulances are directed away from the affected ER.

Howard County Medical Center in Columbia and Sibley Memorial Hospital in Washington, D.C., also went under Code Black on the same afternoon. Both are part of Johns Hopkins Health System. WUSA-TV first reported the Code Black status, according to The Banner.

Kim Hoppe, a Johns Hopkins Health System spokesperson, said a temporary technology network issue triggered the closures.

"We have restored full functionality. This was not a cyber-attack," Hoppe said in a statement Monday.

By 5 p.m. Monday, Suburban Hospital and Howard County Medical Center had cleared Code Black. Sibley Memorial remained under the restricted status at that time.

Johns Hopkins did not disclose when the Code Black began, how long Suburban's ER was closed to ambulances, or what specifically went wrong with the network. The Maryland Department of Emergency Management did not respond to The Banner's request for comment Monday, The Banner reported.

The incident came days after a separate cyberattack struck two other Maryland hospitals. Anne Arundel Medical Center in Annapolis and Doctors Community Medical Center in Lanham, both operated by Luminis Health, confirmed a cybersecurity breach on Friday, Sept. 4, that forced some ambulances to reroute non-critical patients, WYPR reported. Hoppe's statement explicitly ruled out a cyberattack as the cause of Monday's Hopkins outage.

Montgomery County emergency scanner account @MoCoFireWire flagged Suburban's Code Black status on X on Monday, drawing more than 7,600 impressions.

@MoCoFireWire: "Suburban Hospital is on Code Black. Exact situation is unknown."

Johns Hopkins has not announced any review or public briefing related to the network failure. Residents who experience a medical emergency can check real-time ER status on the state's EDAS dashboard.