A fourth representative announced Tuesday a positive COVID-19 test result following the Jan. 6 joint session of Congress.
Rep. Brad Schneider (D-Ill.) said he tested positive on Tuesday morning.
"Several Republican lawmakers in the room adamantly refused to wear a mask," he said in a statement.
Schneider, 59, said he's showing no symptoms and is isolating.
Rep. Pramila Jayapal (D-Wash.) said Monday she'd tested positive for the disease.
"Many Republicans still refused to take the bare minimum COVID-19 precaution and simply wear a damn mask in a crowded room during a pandemic—creating a superspreader event," or an event where a multiple people contract the new illness, Jayapal said in a statement. She called for fines to be levied on members who refuse to wear masks in the Capitol.
Dr. Brian Monahan, the attending physician of the United States Congress, told members after the session that they may have been exposed to another person with COVID-19 because of the close proximity while sheltering in place. He said members should get tested as a precaution.
People can contract the CCP virus from others, whether they have masks or not. Some experts say wearing masks can lower the chances of transmission of the virus.
Jayapal, who has been quarantining since Jan. 7, didn't say whether she is showing any symptoms. Her office didn't immediately return an inquiry.
Rep. Chuck Fleischmann (R-Tenn.) also tested positive in recent days. He pinned what happened on exposure to "another infected member of Congress" with whom he shares a residence in Washington.
Fleischmann said he was feeling "OK" and isolating as he continued to work. "I again, want to urge all Americans to continue to wear masks, practice proper hygiene, and follow CDC guidance as we work to combat COVID-19," he added in a statement.
Reps. Kay Granger (R-Texas), Michelle Steel (R-Calif.), Gus Bilirakis (R-Fla.), and Kevin Brady (R-Texas) missed the joint session because they recently tested positive for COVID-19. Rep.-elect Maria Salazar (R-Fla.) still hasn't been sworn in after testing positive late last year.