- What You Are Actually Studying For
- Settle Eligibility and Project Sheets Before You Open a Book
- Exam Mechanics: 120 Questions, Three Hours, Closed Book
- The Five Competency Areas, Topic by Topic
- Building Your Reference Stack
- Sequencing Your Preparation Around the Five Areas
- Practice Questions That Match the Exam
- Fees, Scheduling and Test-Day Logistics
- What the Public Pass Data Does and Does Not Tell You
- After You Pass: Renewal, Florida Licensing and Career Context
- Frequently Asked Questions
- The exam is 120 multiple-choice questions in three hours, closed book, with a 75% passing score.
- Prepare across five published competencies: asbestos, lead, hazardous materials, microbial/allergens, and chemicals, each covering controls, removal methods...
- Experience must span at least three of five disciplines, documented on four project sheets, so start those early.
- ACAC's handbook warns its sample pages are not exhaustive; study the full reference list, including 40 CFR 763 and 29 CFR 1926.1101.
What You Are Actually Studying For
The credential covered here is the Council-certified Indoor Environmental Supervisor (CIES), issued by the American Council for Accredited Certification (ACAC) and accredited by the Council for Engineering and Scientific Specialty Boards (CESB). It is a supervisor-level certification for people who plan, direct and verify remediation work in indoor environments. Other credentials share the same four-letter acronym, so confirm that any prep material you buy is written for this ACAC credential. If you want the basics of the name first, see our explainer on what CIES certification is.
Two points shape everything that follows. First, the exam is not mold-only. Mold and microbial work is one of five competency areas, and asbestos, lead, hazardous materials and chemicals carry just as much weight in your preparation. Second, the credential is built around experience. Passing the test is one step; ACAC board approval of your documented field work is the other. This guide walks through both, and you can compare it with our deeper pieces on the five content areas and how hard the exam is.
Settle Eligibility and Project Sheets Before You Open a Book
Many candidates treat the application as paperwork to finish after studying. For this credential, the application is a major workload in its own right, and it can run on a timeline you do not fully control.
The three experience pathways
| Education | Documented indoor environmental remediation experience |
|---|---|
| Related four-year degree, or 30 qualifying college credits | Four years |
| Related two-year degree, or 15 qualifying credits | Six years |
| High school diploma or GED | Eight years |
Whichever pathway applies, your experience must cover at least three of five areas: asbestos; lead; hazardous materials; microbial/allergens; and industrial hygiene, chemicals and toxicology. ACAC's FAQ explains which semester-credit subjects qualify and states that actual field experience is required. Our CIES requirements guide covers the eligibility rules in more detail.
Four project sheets
You must submit four project sheets, plus educational evidence where applicable and experience verification. ACAC describes each sheet as three parts: the problem, your own responsibilities and actions, and the outcome. The middle part is where weak sheets fail. Describing what the crew did is not enough; the board wants to know what you personally decided, specified, supervised or verified.
An unresolved timing conflict
ACAC's current application page specifies online submission, required email verifications, unanimous board approval, and a six-month window that includes the examination, with the board meeting every four to six weeks. The CIES handbook instead gives 90 days and describes notarized forms and employer affidavits. This conflict exists in the issuer's own materials and has not been resolved publicly. Before you commit to a study calendar, confirm the current timeline and form requirements directly with ACAC, and give yourself margin. Our CIES exam dates guide covers scheduling in more depth.
Exam Mechanics: 120 Questions, Three Hours, Closed Book
The examination is delivered through Kryterion, Inc. Here is what is published:
- Format: 120 multiple-choice questions, each with at least four answer options
- Time: three hours, computer-delivered, closed book
- Passing score: 75%, set using the Modified Angoff method (see our passing score breakdown)
- Delivery: proctored testing center or online video proctoring
- Item handling: a fixed question set with randomized item and answer order; adaptive testing is not described
- Results: available electronically immediately and confirmed by email
Some details are not published: the split between scored and unscored questions, and whether a calculator is permitted. Do not assume either way. If you expect to need exposure-limit or dilution arithmetic, practice doing it by hand and confirm the calculator policy with ACAC before test day. No separate practical assessment is described, so everything is tested through written multiple-choice items.
Three hours for 120 questions works out to a generous pace of roughly a minute and a half per item. The real challenge is not speed but breadth: questions can move from asbestos work-practice controls to lead-safe containment to solvent exposure in rapid succession.
The Five Competency Areas, Topic by Topic
The handbook publishes five competency headings. They are unweighted preparation topics: ACAC does not publish percentages, a highest-weighted area, or an official exam-domain count, so treat any source quoting weights with skepticism. What the handbook does say is that each competency addresses engineering controls, cleaning and removal methods, worker safety, and applicable regulations. Use that four-part lens on every area.
Domain 1: Understand and execute successful remediation of asbestos in the indoor environment
Expect to reason through abatement from the supervisor's chair, not just recite definitions.
- Regulatory frameworks: 40 CFR 763 (asbestos in schools), 40 CFR 61 Subpart M (NESHAP) and 29 CFR 1926.1101 (the OSHA construction standard)
- Containment and negative-pressure engineering controls, and how they are set up and verified
- Wet methods, removal techniques, waste handling and disposal
- Worker protection: respiratory protection, decontamination procedures, exposure monitoring
- Clearance logic: when an area can be released for reoccupancy
Domain 2: Understand and execute successful remediation of lead in the indoor environment
This area pairs residential-oriented rules with worker-exposure rules, and the exam may test which applies when.
- 40 CFR 745 (lead-based paint requirements) and 29 CFR 1926.62 (OSHA lead in construction)
- Work practices that control dust generation, containment, cleaning verification
- Worker safety: exposure assessment, medical surveillance concepts, hygiene facilities, respirator selection
- Waste and cleanup methods appropriate to lead dust and debris
Domain 3: Understand and execute successful remediation of hazardous materials in the indoor environment
This is the broadest area and the one most mold-only trainees underestimate.
- 29 CFR 1910.120 (HAZWOPER) and the planning, site control and emergency-response concepts behind it
- Mercury cleanup, including the handbook's reference materials on mercury response
- Drug-lab contamination, using the EPA Voluntary Guidelines for Methamphetamine Laboratory Cleanup
- Characterizing unknown materials, segregation, packaging and disposal logic
Domain 4: Understand and execute successful remediation of microbial contaminants and allergens in the indoor environment
Mold remediation principles anchor this area, but allergens extend beyond fungi.
- The New York City Department of Health and Mental Hygiene Guidelines on Assessment and Remediation of Fungi in Indoor Environments (2008)
- Moisture source identification and control as the precondition for any cleanup
- Containment tiers, HEPA filtration, cleaning versus removal of affected materials
- Protecting occupants and workers; post-remediation verification concepts
Domain 5: Understand and execute successful remediation of chemicals in the indoor environment
This competency draws on industrial hygiene and toxicology fundamentals.
- Routes of exposure, dose-response thinking and exposure assessment basics
- Ventilation and other engineering controls versus administrative controls and PPE
- Respirator selection, including the NIOSH Respirator Selection Logic (2004)
- Cleaning and removal methods for chemical contamination, plus applicable regulations
Building Your Reference Stack
The handbook's listed preparation references form the backbone of your library. Gather them and read the primary sources rather than summaries:
- ACAC Code of Conduct (easy to overlook; ethics questions are fair game)
- 40 CFR 763 and 40 CFR 61 Subpart M (asbestos)
- 29 CFR 1926.1101 (asbestos, OSHA construction)
- 40 CFR 745 and 29 CFR 1926.62 (lead)
- 29 CFR 1910.120 (hazardous waste operations and emergency response)
- NYC DOHMH fungi guidelines (2008)
- NIOSH Respirator Selection Logic (2004)
- EPA Voluntary Guidelines for Methamphetamine Laboratory Cleanup
The mercury reference discrepancy
The handbook's body-of-knowledge section and its study-guide section describe the mercury material differently, naming EPA Region 5 (section 5) in one place and the National Elemental Mercury Response Guidebook (section 9.4) in the other. Rather than guess which is authoritative, read both sources and focus on the principles they share: spill characterization, containment, vapor control and worker protection.
Note that a publication date on a reference is not an exam-version date. The public handbook is undated and no separately identified 2026 exam version has been verified, so recheck ACAC's page before you finalize your reading list. For a condensed companion, our CIES cheat sheet collects the must-know facts in one place.
Sequencing Your Preparation Around the Five Areas
Because the five competencies share a four-part structure (controls, removal methods, worker safety, regulations), the most efficient plan is to build a single comparison grid early and fill it in as you move through each area. Order matters: begin with the rule-heavy areas while your energy is highest, and finish with the broader judgment-based ones.
Asbestos
- Read 29 CFR 1926.1101, then 40 CFR 61 Subpart M and 40 CFR 763; note which rule governs which setting
- Build your first column of the controls/removal/safety/regulation grid
Lead
- Contrast 40 CFR 745 with 29 CFR 1926.62; the overlap is a likely source of tricky distractors
- Draft your first project sheet while the material is fresh
Hazardous materials and chemicals
- Work through 29 CFR 1910.120, mercury references and the methamphetamine cleanup guidance
- Study respirator selection logic alongside exposure-control hierarchy
Microbial and allergens
- Study the NYC fungi guidelines with an emphasis on moisture control and containment levels
- Many practitioners are strongest here, so use the time to find gaps rather than repeat what you know
Integration
- Take timed 120-question sets and review every miss against its source document
- Finalize your remaining project sheets and recheck the application timeline
The eight-week frame is a suggestion, not an ACAC requirement; no minimum training hours or mandatory prep course is published. Stretch or compress it based on how much of the five-discipline experience you have actually lived. A candidate with a decade in asbestos abatement and little chemical exposure should spend proportionally more time on Domains 3 and 5.
Practice Questions That Match the Exam
ACAC does not develop or administer preparation courses, and its prep-course directory did not explicitly list this credential. That leaves candidates assembling their own materials, and quality varies. Free-form document-sharing sites carry exam-labeled files, but their answer accuracy and alignment with the actual reference list cannot be verified, and some preview content is generic professional-process material rather than remediation-specific. Treat any question bank as unverified until its explanations cite the regulations above.
Good practice items for this exam have three traits:
- They are scenario-based, asking what a supervisor should do, not what a term means.
- They span all five competencies rather than clustering on mold.
- Their explanations point back to a specific standard or guideline so you can verify the logic yourself.
When you review misses, categorize each as a regulatory-recall error, an engineering-control error, a worker-safety error or a reading error. Patterns show quickly. You can try scenario-style questions on our CIES practice test site and use the explanations to point you back to the primary documents.
Fees, Scheduling and Test-Day Logistics
Fees in USD
| Item | Amount |
|---|---|
| Examination fee | $100 |
| Certification fee (includes $100 nonrefundable processing fee) | $400 |
| Initial total, first two-year term | $500 |
| Retake | $100 |
| Renewal | $400 |
ACAC publishes no separate member and non-member schedule. See the CIES certification cost breakdown for planning, and confirm current figures at ACAC's fees page since schedules change.
Test-day requirements
- Testing center: two government-issued IDs, including one photo ID. ACAC's current examinations page asks for arrival 15 minutes early, while the handbook says 30. Plan for the longer buffer.
- Online proctoring: you supply the computer, an approved webcam and a private location. ACAC specifies at least 2 Mbps upload and download, and phones and tablets are excluded. Run a connection check well ahead of the exam.
What the Public Pass Data Does and Does Not Tell You
Be wary of any site that quotes a confident CIES pass rate. No numerical 2025 or 2026 rate has been verified. ACAC's accredited certification activity report as of December 31, 2025 shows dashes for applicants and pass ratio, along with 6 recertifications and 6 current certifications; a dash is not a 0% pass rate. The credential is omitted from the 2025 exam pass ratio report.
Older data conflicts. The 2024 pass ratio report lists 2 exams taken, 2 passed, 100%, while the 2024 activity report lists 2 applicants, 0% and 7 current certifications. With samples this small, neither figure says anything reliable about difficulty, and attempt counts include retakes and candidates testing only for state licensing, so they do not measure first-attempt success. The honest takeaway: this is a small, experience-gated credential, and your odds depend on your preparation rather than any published statistic. For a fuller discussion, read what the pass rate data shows.
After You Pass: Renewal, Florida Licensing and Career Context
Renewal
Certification lasts two years. ACAC's current recertification procedures specify 40 recertification credits: 10 for continued field activity and 30 for professional development, with attestation and evidence retained in case of audit. Other ACAC pages describe the requirement differently (a general 40 credits in the handbook, and 20 professional-development hours annually on the program page), so follow the procedures page and keep documentation for everything.
Florida and other licensing contexts
Some candidates take this exam because a state licensing route recognizes it. Indexed Florida Department of Business and Professional Regulation content lists it among mold-remediation examinations, though direct retrieval of that page was blocked during our review. Passing an approved exam is only one part of Florida licensing; separate application, education or experience, fingerprinting and insurance requirements also apply. State licensing eligibility and ACAC certification eligibility are distinct, and a licensing-only exam result does not by itself confer certification. Verify current rules with the regulator before you plan around it.
Career context
Employers that value a supervisor credential tend to be remediation contractors, environmental consulting firms, industrial hygiene practices and facility owners who manage contaminated-building projects. Because the certification demands documented experience across multiple disciplines, it signals breadth. No reliable salary survey specific to ACAC holders has been verified, so be cautious with any earnings claim. For a balanced view, see our salary analysis, the ROI discussion and the overview of CIES jobs. If you are weighing it against ACAC's mold-focused or other remediation credentials, compare scope and experience requirements, not just titles.
Key Takeaway
Treat preparation as two parallel tracks: build the five-discipline knowledge from primary sources, and document your field experience on project sheets that show what you personally did. Candidates who start the paperwork early avoid being squeezed by the application window.
Frequently Asked Questions
The exam has 120 multiple-choice questions with at least four options each, delivered in three hours, closed book. The passing score is 75%, set using the Modified Angoff method. The scored versus unscored split is not published.
No. ACAC's published competencies cover asbestos, lead, hazardous materials, microbial contaminants and allergens, and chemicals. Mold is part of one of the five areas, so mold-only training leaves large gaps.
Yes. Both proctored testing-center and online video delivery are available. Online candidates need a computer, an approved webcam, a private location and at least 2 Mbps upload and download. Phones and tablets are excluded.
A retake costs $100. Scores are available electronically right after the exam, so you will know your result immediately and can review weak competency areas before rescheduling.
No mandatory preparation course or minimum training-hour requirement is published, and ACAC does not develop or administer prep courses. Candidates are expected to study the handbook's references comprehensively on their own.
For more on how the credential is defined and where it fits, revisit our overview of what CIES is, and keep the CIES study guide bookmarked as you work through each competency area.