Washington ( CNN ) -- The House of Representatives side of the U.S. Capitol is closed Thursday because of a construction-related incident , officials said . Police spokeswoman Kimberly Schneider said the incident is confined and not suspicious . A piece of ceiling fell down around 3 a.m. , exposing a chemical substance in a work area . Schneider did not know if the ceiling fell on a container , or whether the substance is liquid . Hazardous materials crews were on the scene . Laura Condeluci , spokeswoman for the Architect of the Capitol , said there was a `` potential release '' during `` asbestos abatement work '' on the House of Representatives side . `` Samples have been collected to determine whether there was potential exposure , '' Condeluci said .
The incident is confined and not suspicious , a police spokeswoman says . She says a piece of ceiling fell around 3 a.m. , exposing a chemical in a work area . Hazardous materials crews are on the scene . Architect of the Capitol : There was a `` potential release '' during `` asbestos abatement work ''