Workplace Mold

Workplace Mold and Your Health

Key points

  • Indoor dampness and mold result from water leaks in buildings.
  • Exposures in damp buildings are complex. They vary from building to building and in different places within a building.
  • Dampness and mold are associated with various respiratory and non-respiratory health problems in workers.
Mold under wallpaper.


Sources of water incursion are often apparent like leaks in the roof or windows or a broken pipe. Sources of water incursion are less obvious when affected materials and water sources are hidden.

Examples include wet insulation in a ceiling or moisture in building foundation due to sloping of surrounding land.

Problems occur when materials in buildings become wet for extended periods of time. Excessive moisture in the air, such as high relative humidity, can also lead to excessive dampness.

Moisture allows indoor mold to grow and multiply on building materials and surfaces. People inside damp buildings may be exposed to microbes, compounds released by microbes, and their structural components, such as spores and fungal fragments.

Mold can produce substances that may cause or worsen health problems. These substances vary depending on the mold species and on conditions related to the indoor environment. Moisture can also attract cockroaches, rodents, and dust mites. Moisture-damaged building materials can release volatile organic compounds or irritating airborne chemicals that may be associated with health problems.


Dampness and Mold Assessment Tool

Researchers have not found exactly how much exposure to dampness-related substances it takes to cause health problems. Studies report that finding and promptly correcting sources of dampness is more effective at preventing health problems than collecting and analyzing air samples for indoor microbes. NIOSH developed a tool to help assess areas of dampness and prioritize remediation of problems areas in buildings.

DMAT covers for schools and general buildings.
DMAT forms with instructions for schools and general buildings.


Occupants within damp buildings, schools, and other nonindustrial buildings may develop respiratory symptoms and disease.

This Alert:

  • Describes respiratory problems that occupants may experience from exposures in damp buildings.
  • Presents information on outbreaks of building-related respiratory disease.
  • Recommends ways to find, respond to, and prevent building dampness and related respiratory symptoms and disease.

NIOSH Alert: Preventing Occupational Respiratory Disease from Exposures Caused by Dampness in Office Buildings, Schools, and Other Nonindustrial Buildings

  • Cho SJ, Cox-Ganser JM, Park J-H [2015]. Observational scores of dampness and mold associated with measurements of microbial agents and moisture in three public schools. Indoor Air 26(2):168-178,
  • Park J-H and Cox-Ganser JM [2022]. NIOSH dampness and mold assessment tool (DMAT): Documentation and data analysis of dampness and mold-related damage in buildings and its application. Buildings 12(8):1075,