The House side of the U.S. Capitol reopened Thursday morning after a brief shutdown because of an asbestos-related incident.

Authorities were keeping one section of the building sealed off for further inspection, but lawmakers and aides returned to work, tours resumed, and the House was planning to reconvene around noon as scheduled.

Earlier, all lawmakers and aides who work on the House side of the Capitol were instructed to stay away “until further notice” by the Architect of the Capitol (AOC), the office that is responsible for management and maintenance of the building.

Officials initially described the incident only as an “industrial spill.”

The AOC said in a statement that during ongoing asbestos-removal work, “there was a potential release affecting the House side of the Capitol.” Samples were collected to determine whether there was potential widespread exposure.

In addition to overseeing multimillion-dollar renovations to the Capitol Dome, the AOC is having asbestos removed from other parts of the building.

Initial news reports Thursday morning said the incident occurred when workers were removing asbestos from the fourth floor of the Capitol and something fell.

The House is scheduled to hold votes Thursday afternoon and evening to approve spending bills to fund the Energy and Treasury departments.

The brief closure on the House side did not affect the Senate, which occupies the north side of the Capitol and was expected to convene Thursday as scheduled. U.S. Capitol Police officers are able to cordon off parts of the building and keep out lawmakers, aides, reporters and visitors if necessary.