The City of Las Vegas has ordered the Endoscopy Center of Southern Nevada to close its doors after six patients who underwent procedures there were diagnosed with hepatitis C virus.

City officials revoked the business license for the clinic on Friday afternoon.

“The city now has the business license in hand. They don’t have a license to do business in the city of Las Vegas. They might not ask for a hearing. We may just keep the license in our possession indefinitely,” Las Vegas Mayor Oscar Goodman told local Las Vegas Review-Journal.

Southern Nevada Health District officials also recommended nearly 40,000 people who received anesthesia at the Endoscopy Center of Southern Nevada between March 2004 and January 11 of this year be tested for all trains of hepatitis as well as HIV.

“As a precaution, and in order to take appropriate steps to protect their health, it is important for these patients to get tested and for anyone with the illness to seek medical treatment,” the statement said.

The local prosecutors’ office said it was closely examining the case and raised the possibility of filing charges against the center. Moreover, some former patients had contacted lawyers for a possible class action suit against the clinic, local media reported.

The clinic did not comment on the allegations, but expressed concern for patients infected.

“We wish to emphasize that the actual risk of anyone being affected by this is extremely low, but as a precaution, anyone who has undergone procedures at the Endoscopy Center who required anesthesia should be tested,” the statement said.