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100+ Free CMC Practice Questions

Pass your ACAC Council-certified Microbial Consultant (CMC) exam on the first try — instant access, no signup required.

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Question 1
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Per S500, Class 1 water intrusion is defined as:

A
B
C
D
to track
2026 Statistics

Key Facts: CMC Exam

120

Exam Questions

ACAC Candidate Handbook

75%

Passing Score

ACAC Candidate Handbook

3 hours

Exam Duration (closed-book)

ACAC Candidate Handbook

$500

Total Fee ($400 cert + $100 exam)

ACAC fees page

8 years

Field Experience (4 yrs with 4-yr degree)

ACAC

CESB

Accreditation Body

ACAC

40 RCs

Recertification Credits per 2-year Cycle

ACAC

The ACAC CMC (Council-certified Microbial Consultant) is the senior microbial consulting credential issued by the American Council for Accredited Certification (ACAC) and is accredited by the Council for Engineering and Scientific Specialty Boards (CESB). It is the most rigorous certification in the ACAC microbial track, intended for experienced consultants who design sampling strategies, interpret complex lab data, provide expert testimony, and lead multi-disciplinary investigations. The 120-question, 3-hour, closed-book exam (75% passing score) covers microbial risk analysis, advanced sampling and lab QA/QC, building science, ANSI/IICRC S520, ANSI/IICRC S500, ASTM D7338, and consulting practice. Prerequisites: 8 years of field experience (reduced to 4 years with a 4-year science/engineering degree, or 6 years with a 2-year degree). Certification is valid for 2 years and requires 40 Recertification Credits and unanimous approval of the CMC certification board.

Sample CMC Practice Questions

Try these sample questions to test your CMC exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which is the senior microbial consulting credential offered by ACAC, accredited by CESB?
A.CMI
B.CRMI
C.CMC
D.CMR
Explanation: The Council-certified Microbial Consultant (CMC) is the senior, CESB-accredited consulting credential in ACAC's microbial track. CMI is investigator-level; CRMI is residential inspector; CMR is remediator.
2Per ACAC's microbial consulting handbook, the CMC examination consists of how many questions?
A.75
B.100
C.120
D.150
Explanation: ACAC's CMC examination is a 120-question, 3-hour, closed-book examination. A 75% passing score is required.
3ACAC requires CMC candidates WITHOUT any qualifying degree to have how many years of documented field experience in mold inspection/sampling?
A.2 years
B.4 years
C.6 years
D.8 years
Explanation: ACAC requires 8 years of documented field experience for the CMC. The requirement is reduced to 4 years with a 4-year science/engineering degree, or 6 years with a 2-year degree.
4Sterigmatocystin, a metabolite of Aspergillus versicolor, is classified by IARC as:
A.Group 1 (carcinogenic to humans)
B.Group 2A (probably carcinogenic to humans)
C.Group 2B (possibly carcinogenic to humans)
D.Group 3 (not classifiable)
Explanation: Sterigmatocystin is classified by IARC as Group 2B — possibly carcinogenic to humans. It is structurally related to aflatoxin B1 (Group 1) and is produced primarily by A. versicolor and some related species.
5Which mycotoxin class is most commonly produced by Stachybotrys chartarum?
A.Aflatoxins
B.Ochratoxins
C.Macrocyclic trichothecenes
D.Fumonisins
Explanation: Stachybotrys chartarum produces macrocyclic trichothecenes (e.g., satratoxins G and H, roridin E, verrucarin J). Some Fusarium species produce simple (non-macrocyclic) trichothecenes such as T-2 toxin and deoxynivalenol.
6Which method is BEST for chronologically integrating a building's mold burden over months?
A.Single 5-minute Air-O-Cell sample
B.Dust-based ERMI (qPCR of settled dust)
C.Direct microscopy of a tape lift
D.OSHA respirator fit test
Explanation: ERMI quantifies species-specific DNA in dust, which integrates spore deposition over time. Spot air samples are point-in-time snapshots. Tape lifts characterize specific surfaces but do not integrate temporally.
7An indoor environmental consultant designing a sampling strategy for a litigation-support case should prioritize which principle?
A.Use the cheapest available method
B.Hypothesis-driven sampling with defensible QA/QC and chain-of-custody
C.Take as many random samples as the budget allows
D.Skip outdoor reference samples to save time
Explanation: Defensible work requires a written hypothesis, sampling plan tied to that hypothesis, AIHA-LAP-accredited analysis, full QA/QC, and chain-of-custody. Random or unfocused sampling weakens defensibility.
8Which lab accreditation specifically applies to U.S. environmental microbiology labs analyzing mold samples?
A.AIHA-LAP EMLAP
B.ISO 9001 only
C.OSHA VPP
D.GLP for pharmaceuticals
Explanation: The AIHA-LAP Environmental Microbiology Laboratory Accreditation Program (EMLAP) accredits labs performing environmental microbiology including direct microscopy, viable analyses, and qPCR. Other certifications are not specific to environmental microbiology.
9When acting as IEP, what is the BEST first step after a CMC arrives at a building with reported water damage and complaints?
A.Begin sampling immediately
B.Conduct a thorough building walk-through with occupant interview and visual/moisture mapping before any sampling
C.Apply biocide preventively
D.Order demolition
Explanation: A defensible investigation begins with occupant interviews, building walk-through, moisture mapping, and visual documentation. Sampling is hypothesis-driven and follows this initial assessment, not the other way around.
10ANSI/IICRC S500 Category 3 water includes which of the following?
A.Broken supply line from a water heater
B.Sewage backflow, rising surface water, and seawater intrusion
C.Dishwasher discharge
D.Condensate from an air handler
Explanation: Category 3 water is grossly contaminated and includes sewage, rising ground/surface water, and seawater. Broken supply lines start as Cat 1; dishwasher discharge is Cat 2; HVAC condensate is typically Cat 1 if clean.

About the CMC Exam

The CMC is the senior microbial consulting credential from ACAC, certifying competence in advanced microbial investigation, building forensics, risk analysis, and consulting practice. The 120-question exam is the most rigorous in the ACAC microbial track and is accredited by CESB.

Questions

120 scored questions

Time Limit

3 hours

Passing Score

75%

Exam Fee

$500 (certification + exam) (ACAC (American Council for Accredited Certification))

CMC Exam Content Outline

~20%

Microbial Risk Analysis & Ecology

Mycotoxins, bioaerosol exposure, dose-response, sensitive populations, indicator vs. allergenic vs. toxigenic species

~20%

Advanced Sampling & Lab QA/QC

Air-O-Cell, Andersen N6, qPCR-based ERMI/HERTSMI-2, AIHA-LAP EMLAP, field blanks, chain-of-custody

~20%

Building Science & Forensic Investigation

Vapor drive, dew point, HVAC pathways, hidden mold, infrared thermography, forensic methodology

~20%

Standards, Codes & Regulations

ANSI/IICRC S520, S500, ASTM D7338, EPA, NIOSH, OSHA general duty, state mold programs

~20%

Consulting Practice, Reporting & Ethics

Scope of work, expert testimony, conflict of interest, separation of assessment from remediation, ACAC Code of Ethics

How to Pass the CMC Exam

What You Need to Know

  • Passing score: 75%
  • Exam length: 120 questions
  • Time limit: 3 hours
  • Exam fee: $500 (certification + exam)

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

CMC Study Tips from Top Performers

1Master sampling strategy — when to use Air-O-Cell vs. Andersen N6 vs. ERMI vs. surface sampling — the CMC exam tests hypothesis-driven decisions, not just procedure
2Know mycotoxin chemistry — sterigmatocystin (Aspergillus versicolor, IARC Group 2B), trichothecenes (Stachybotrys), and ochratoxin (Aspergillus, Penicillium)
3Study lab QA/QC: AIHA-LAP EMLAP accreditation, analyst proficiency testing, field blanks, and how analytical limits of detection affect interpretation
4Understand building science: vapor drive direction (warm to cold, high vapor pressure to low), dew point calculations, and HVAC pathways for moisture/contaminant migration
5Know the state regulatory landscape — NY Mold Law (Article 32), Florida, Texas, and other states with mold professional licensing
6Review the ACAC Code of Ethics — separation of assessment from remediation, conflict of interest, and limits of scientific certainty in expert testimony

Frequently Asked Questions

What is the CMC exam?

The CMC (Council-certified Microbial Consultant) exam is the senior microbial consulting credential from ACAC (American Council for Accredited Certification). It tests advanced competency in microbial risk analysis, sampling strategy, building forensics, lab QA/QC, ANSI/IICRC S520 standards, and consulting practice.

How many questions are on the CMC exam?

The ACAC CMC exam contains 120 multiple-choice questions delivered as a 3-hour, closed-book examination through Kryterion testing centers. A score of 75% is required to pass.

How is the CMC different from the CMI?

The CMI (Council-certified Microbial Investigator) is the standard investigator credential requiring 2 years of field experience. The CMC (Council-certified Microbial Consultant) is the senior consulting tier requiring 8 years of experience (or 4 years with a 4-year degree) and unanimous board approval. The CMC exam has 120 questions vs. 100 for the CMI, and CMC holders typically lead complex investigations, design sampling strategies, and provide expert testimony.

Is the CMC accredited?

Yes. The CMC is accredited by the Council for Engineering and Scientific Specialty Boards (CESB), a nationally recognized independent accreditation body. This makes the CMC one of the highest-tier microbial consulting credentials available.

What are the prerequisites for the CMC credential?

ACAC requires 8 years of documented field experience in mold inspection and sampling. This is reduced to 4 years with a 4-year college degree in science, engineering, or a related field, or 6 years with a 2-year degree. Candidates must also receive unanimous approval from the CMC certification board and agree to the ACAC Code of Ethics.

How long is the CMC certification valid?

The CMC certification is valid for 2 years from the date of issue. Holders must accumulate 40 Recertification Credits (RCs) — each representing 1 hour of continuing education or professional development — prior to expiration to maintain the credential.

How long should I study for the CMC exam?

Most candidates prepare for 100-150 hours over 8-12 weeks. Prioritize advanced sampling strategy, mycotoxin risk analysis, ANSI/IICRC S520 condition classifications, building forensics (vapor drive, dew point, HVAC pathways), and the regulatory landscape (NY Article 32, EPA, NIOSH, OSHA general duty).