How to Recognize Mold

Mold may be recognized by:

• Sight – They usually appear as distinctly

colored woolly mats (e.g., mildew is black

and is one of the most common molds in a

household). 

• Smell – They often produce a foul odor,

such as a musty, earthy smell.

Preventing Mold Growth

The key to mold prevention is moisture control. Mold will not grow if moisture is

absent.

• Remove excess moisture with a wet-dry

vacuum and dry out the building as quickly

as possible (preferably within 24 to 48

hours).

• Use fans to assist in the drying process. 

• Clean wet materials and surfaces with

detergent and water. 

• Discard all water damaged materials. 

• Discard all materials visibly contaminated

with mold.

• Remove and discard all porous materials

that have been wet for more than 48 hours.

Porous materials cannot be cleaned and

may remain a source of mold growth.

These materials include the following:

◆ Carpeting and carpet padding; 

◆ Upholstery, wallpaper, drywall; 

◆ Floor and ceiling tiles, insulation materials; 

◆ Clothing; 

Health Effects of Mold Exposure

Molds can cause mild to severe health problems in sensitive individuals when a sufficient

number of airborne spores are inhaled. Some

individuals are far more sensitive than others.

The most common health effects associated

with mold exposure are allergic reactions.

Symptoms may include:

• Sneezing

• Runny nose

• Eye irritation

• Cough

• Congestion

• Aggravation of asthma 

• Dermatitis (skin rash)

People at Greatest Risk 

Infants, children, and the elderly are more

susceptible to health problems attributable

to molds. In addition, people with the following underlying health conditions may be

more sensitive to molds:

• Individuals with allergies or existing respiratory conditions including asthma, sinusitis, or other lung diseases.

• Individuals with a weakened immune system (e.g., HIV patients).

• Recent organ or bone marrow transplant

patients.

• Patients recovering from recent surgery

and receiving chemotherapy or long-term

steroid treatment.

FactSheet

Mold

Molds are the most common forms of fungi found on earth. They can grow on

almost any material, as long as moisture and oxygen are available. Most molds

reproduce through the formation of spores, tiny microscopic cells that are resistant to drying and are released into the air. Airborne spores are found both

indoors and outdoors. When spores land on a suitable moist surface, they begin

to grow and release chemicals that digest and can eventually destroy the surface

and underlying materials. Molds can also cause adverse health effects. 
◆ Leather; 

◆ Paper, wood; 

◆ Food.

• Homeowners may want to temporarily

store items outside of the home until insurance claims can be filed.

General Cleanup Tips

• Make sure the working area is well ventilated.

• Place mold damaged materials in a plastic

bag and discard.

• Clean mold off hard surfaces and other

nonporous materials with detergent and

water, and dry completely.

• Disinfect these cleaned surfaces with one

of the following household bleach solutions:

◆ 1/4 cup household bleach per 1 gallon of

clean water for light contamination.

◆ 11/2 cups household bleach per 1 gallon

of clean water for heavy contamination. 

This is one in a series of informational fact sheets highlighting OSHA programs, policies or 

standards. It does not impose any new compliance requirements. For a comprehensive list of 

compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal

Regulations. This information will be made available to sensory impaired individuals upon request.

The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.

CAUTION: Do not mix bleach with other

cleaning products that contain ammonia.

Highly toxic chlorine gas can be produced. 

• Avoid breathing mold spores. A N-95 respirator is recommended.

• Avoid touching mold with your bare hands.

Long gloves that extend to the middle of

the forearm are recommended. Use ordinary household rubber gloves when cleaning surfaces with water, bleach, and a mild

detergent. Gloves made from natural rubber, neoprene, nitrile, polyurethane, or PVC

are recommended if using a disinfectant,

biocide, or strong cleaning solution.

• Avoid getting mold spores in your eyes.

Goggles without ventilation holes are recommended.

Additional Information

Visit OSHA’s Safety and Health Topics 

webpage on Molds and Fungi at

http://www.osha.gov/SLTC/molds/index.html

U.S. Department of Labor

www.osha.gov

(800) 321-OSHA

For more complete information:

DSG 9/2005