Cladosporium Mold in Your Home: Is It Dangerous?
Cladosporium is among the most common molds indoors and out. Is it dangerous, what does a lab report naming it mean, and does the name change the cleanup?
A lab report says "Cladosporium," or someone told you that's the mold you found, and you want to know what it means. That's the right instinct. It's one of the most common molds in the air, and CDC lists it with Penicillium and Aspergillus as the most common indoor molds. CDC treats it like any other mold for potential health risks and removal.
In This Guide
- What is Cladosporium?
- Is Cladosporium mold dangerous?
- What does it mean if a mold test finds Cladosporium?
- Does Cladosporium need a different cleanup?
- Cleaning up Cladosporium in your house
- Frequently asked questions
What is Cladosporium?
The name Cladosporium covers a genus of related molds, not one species, and it's among the most common fungi in the air; a 2012 revision of the genus recognized 169 species. Outdoors it lives on plant debris and soil. CDC says mold in the air outside "can be brought indoors on clothing, shoes, bags, and even pets."
What does Cladosporium look like?
No one can confirm Cladosporium by eye or from a photo. A lab looking at a sample directly under a microscope can report Cladosporium at the genus level. Culture-based analysis, where the lab first grows the mold from the sample, usually identifies fungi to genus and sometimes to species. CDC's general mold page says mold "can look like spots of many different colors" and gives Cladosporium no color. On a lab plate, its colonies can include olive-brown to blackish-brown shades.
Is Cladosporium mold dangerous?
"Exposure to damp and moldy environments may cause a variety of health effects, or none at all," CDC says, and it doesn't rank Cladosporium against other molds. Some people may get a stuffy nose, sore throat, coughing or wheezing, burning eyes or a skin rash, CDC says. People with asthma or a mold allergy may react severely.
On its page about Stachybotrys chartarum, CDC says "all molds should be treated the same with respect to potential health risks and removal" (CDC). Some molds can cause allergic or irritant effects in susceptible people; certain fungi can cause serious infections in people with specific medical risks. A photograph cannot determine the organism or an individual's health risk.
Is it toxic? EPA says "no one can tell whether a mold is producing mycotoxins just by looking at it." A lab report identifying Cladosporium at the genus level doesn't establish whether mycotoxins are present or being produced. Health questions belong with a healthcare professional.
Is Cladosporium black mold?
EPA says "black mold" "is not a species or specific kind of mold, and neither is 'toxic mold,'" though the news media sometimes use the terms for molds that may produce mycotoxins, or for one mold, Stachybotrys chartarum (EPA). Cladosporium is a genus of its own, and color alone can't reliably identify a mold (black mold look-alikes).
What does it mean if a mold test finds Cladosporium?
On an air-sample report, the name Cladosporium tells you which kind of spore was counted at one moment. What it means depends on what an inspection found, whether there's a moisture problem, the conditions when the samples were taken, and what they're compared with. A single air sample represents one place and moment, not a whole area. The American Industrial Hygiene Association's 2025 guidance notes that research using repeated culture-based air samples in the same room found airborne concentrations varying by as much as 10,000-fold at different times of day.
Why a spore-trap report says Cladosporium, not a species
Routine spore-trap/microscopy analysis generally identifies a genus or broad fungal group rather than a species. Home kits vary. Passive culture plates can grow ordinary viable airborne fungi but do not measure total airborne spore concentration or diagnose a building problem.
What a Cladosporium count can and can't tell you
CDC says "you cannot rely on sampling and culturing to know whether someone might become sick." EPA says spores "cannot be eliminated from indoor environments." An outdoor air sample is a common comparison, and the one EPA uses; a similar room with no suspected problem can also serve when appropriate, and outdoor sampling isn't always practical. We read any comparison as one input alongside the inspection, never a pass or fail. An indoor level clearly above the comparison sample can point to a source indoors, and a low result can miss hidden growth. EPA says limits for airborne mold spores "have not been set" (EPA).
Do you need to test for Cladosporium?
If you can see the mold, usually not: EPA says "in most cases, if visible mold growth is present, sampling is unnecessary." Lab work belongs where it answers a defined question, like documenting the type.
EPA says a site evaluation may include sampling in cases such as litigation, an unclear source or health concerns. ANSI/IICRC S520-2024, the mold remediation standard, says reported health issues should mean an assessment by an independent indoor environmental professional (IEP) or other appropriate professional (§1.2.1), and a required or requested post-remediation verification should come from an independent IEP and can include sampling (§12). An assessment may not need air testing, and symptoms alone aren't a reason for routine sampling. We recommend an assessor who isn't doing the remediation.
Does Cladosporium need a different cleanup?
Not because of the name. CDC says "no matter what type of mold is present, you need to remove it," and that the job depends on "how much water damage your home suffered and where the mold is growing." EPA's schools and commercial buildings guidelines are based on the area and type of material affected, with size groupings meant to help pick techniques, "not on the basis of health effects." Condition, material, extent and moisture drive S520's procedures (§1.5, §7.3.3, §9.3.7), and none names a genus.
However, EPA's schools guide says a more cautious or conservative approach is indicated when a particularly toxic mold species has been identified or is suspected, when extensive hidden mold is expected, when the chances of the mold becoming airborne are estimated to be high, or when sensitive individuals are present (EPA). A test result naming only the genus, Cladosporium, doesn't by itself show that a particularly toxic mold species has been identified.
Cleaning up Cladosporium in your house
Fix the water, clean or remove what's growing, and dry everything. Under about 10 square feet, EPA says, you can in most cases do it yourself. CDC says to wear at least an N95 respirator, protective gloves and goggles without open vent holes, and a half- or full-face respirator for longer work like ripping out drywall. Cover your arms and legs too. Avoid dry brushing, scraping, fanning or other uncontrolled disturbance.
People with allergies, immune suppression, underlying lung disease, or chronic respiratory diseases like asthma or COPD shouldn't take part in the cleanup, CDC says. Higher-risk occupants may also need to avoid the affected area during cleanup. EPA says to consult a health professional first if you have health concerns, call an experienced professional for sewage or other contaminated water, skip running a heating or cooling system you suspect is contaminated, and consider an experienced professional for hidden mold. We recommend professional help when size, material, disturbance, HVAC involvement, contaminated water, hidden growth, access, or occupant concerns make the work more complex. If health issues are reported, get an independent environmental assessment; questions about a person's health belong with a healthcare professional.