Harris County Public Health, the Texas Department of State Health Services and the U.S. Air Force Reserve will begin an aerial spray for mosquitos Thursday evening throughout Harris County, according to a statement from HCPH. The agencies are working to limit the growth of mosquito populations after flooding from Hurricane Harvey.

The spray operation, which covers 600,000 acres in Harris County, could take more than one day, according to the statement. Cargo planes will spray Dibrom, an insecticide, by air in the affected area. The aerial spray is planned as a supplement to ongoing ground treatment of mosquito populations countywide.

"The goal is to reduce the effects mosquitoes are having on recovery efforts and the possibility of a future increase in mosquito-borne disease," HCPH Executive Director Umair Shah said in a statement.

Although the insecticide is deemed safe for the environment by the Environmental Protection Agency, HCPH officials said residents concerned about exposure to the insecticide should stay indoors during the spray period Thursday evening. Additionally, bee colonies should be covered during the spray period.

Affected ZIP codes are shown in the map below.