- The Short Answer: What a CIES Actually Is
- Who Issues It and Who Stands Behind It
- The Five Remediation Competencies
- How the Exam Works
- Getting Eligible: Experience, Credits and Project Sheets
- Fees, Application Timing and Conflicting Rules
- Certification Versus a State Licensing Exam
- How a CIES Differs From Related ACAC Credentials
- Where the Credential Fits in a Career
- Sequencing Your Preparation Around the Five Domains
- Keeping the Credential Active
- Frequently Asked Questions
- CIES here means Council-certified Indoor Environmental Supervisor, issued by the American Council for Accredited Certification (ACAC).
- The exam has 120 multiple-choice questions, three hours, closed book, with a 75% passing score.
- Candidates need documented field experience in at least three of five areas, plus four project sheets.
- Initial cost is $500 for a two-year term: $100 exam plus $400 certification.
The Short Answer: What a CIES Actually Is
A CIES is a Council-certified Indoor Environmental Supervisor: a professional who has been certified by ACAC as qualified to supervise remediation work in indoor environments. The word "supervisor" matters. This is not an entry-level awareness credential or a classroom-only designation. It is built around people who have actually run or directly managed remediation projects, who can describe a problem, what they personally did about it, and how it turned out.
The credential spans five fields of indoor remediation: asbestos, lead, hazardous materials, microbial contaminants and allergens, and chemicals. Many certifications in this industry focus on a single hazard, most commonly mold. The CIES is deliberately wider, which is why it attracts supervisors who work across hazard types rather than specialists in one.
If you are searching for related phrasing, the same credential is explained from slightly different angles in our pieces on what CIES is, what CIES stands for, and CIES meaning. This article takes the broadest view: what the credential covers, how you qualify, and what the exam asks of you.
Who Issues It and Who Stands Behind It
The credential is issued by the American Council for Accredited Certification through its CIES Certification Board. ACAC's program is accredited by the Council for Engineering and Scientific Specialty Boards (CESB), which gives the certification an independent accreditation backbone rather than leaving it as a purely in-house designation.
The exam itself is delivered through Kryterion, Inc., a testing provider. ACAC does not develop or administer preparation courses, which has two practical consequences. First, there is no mandatory training course or minimum training-hour requirement to sit for the exam. Second, any prep material you buy comes from third parties, and ACAC's own prep-course directory did not explicitly list the CIES at the time of our review. Your most authoritative source remains ACAC's own Candidate Handbook and its Required Skills and Exam Study Guide.
The Five Remediation Competencies
ACAC publishes five competency headings for the CIES. They are unweighted: the public materials do not give percentages, and we have not verified an official exam-domain chart or a highest-weighted area. Treat them as the five preparation topics the issuer has put in writing, not as an exhaustive blueprint. The handbook states that the board prescribes an exam blueprint, but that blueprint is not reproduced publicly.
Each competency addresses the same four threads: engineering controls, cleaning and removal methods, worker safety, and the regulations that apply. That repeated structure tells you what kind of questions to expect: practical, supervisory judgment calls rather than trivia.
Domain 1: Understand and execute successful remediation of asbestos in the indoor environment
Asbestos is the most heavily regulated topic on the list, and the regulatory references reflect that.
- Know the federal asbestos framework in 40 CFR 763 and the NESHAP rule at 40 CFR 61 Subpart M.
- Know the OSHA construction standard at 29 CFR 1926.1101, including worker protection requirements.
- Be able to reason through containment, negative-pressure enclosures, wet methods and waste handling as a supervisor would on site.
Domain 2: Understand and execute successful remediation of lead in the indoor environment
Lead questions blend regulation, work practices and worker exposure control.
- Study 40 CFR 745 for lead-based paint provisions and 29 CFR 1926.62 for the OSHA construction lead standard.
- Understand how cleaning, removal and engineering controls differ for lead dust versus intact painted surfaces.
- Be ready to connect exposure monitoring and worker protection to the work method chosen.
Domain 3: Understand and execute successful remediation of hazardous materials in the indoor environment
This is the broadest and least predictable domain, which makes it a common weak spot.
- Know 29 CFR 1910.120 (HAZWOPER) and the safety logic behind it.
- The handbook's materials reference mercury, and the body-of-knowledge and study-guide descriptions of that material name different sources (EPA Region 5 and the National Elemental Mercury Response Guidebook). Review both so a discrepancy does not catch you off guard.
- The listed references also include EPA's Voluntary Guidelines for Methamphetamine Laboratory Cleanup, so do not skip it.
Domain 4: Understand and execute successful remediation of microbial contaminants and allergens in the indoor environment
Mold is the topic most candidates already know, but the exam context is supervisory, not just technical.
- The New York City Department of Health and Mental Hygiene's Guidelines on Assessment and Remediation of Fungi in Indoor Environments (2008) is a named reference.
- Focus on containment levels, source control, moisture, cleaning and removal methods, and protecting workers and occupants.
- NIOSH Respirator Selection Logic (2004) is relevant here and across the other domains.
Domain 5: Understand and execute successful remediation of chemicals in the indoor environment
Chemical remediation pulls together industrial hygiene, toxicology and hazard communication thinking.
- Understand how chemical hazards differ from particulate hazards in controls and cleanup.
- Be comfortable choosing respiratory protection with a documented logic, not guesswork.
- Connect toxicology basics to exposure limits, monitoring and worker safety decisions.
For a deeper treatment of each area, see our complete guide to all five CIES content areas. One more caution from the issuer: the public study guide says its selected pages are examples, not exhaustive coverage, and advises comprehensive study of the full reference list. Reading the handbook alone is not enough.
How the Exam Works
The exam is a computer-delivered written examination of 120 multiple-choice questions, each with at least four answer options. You have three hours, it is closed book, and the passing score is 75%, set using a Modified Angoff method. The split between scored and unscored questions is not published, and adaptive testing is not described. Whether calculators are permitted is unverified, so confirm with ACAC before test day rather than assuming.
The handbook describes a fixed question set with randomized item and answer order, so two candidates see the same pool in different sequences. Scores are available electronically right away and confirmed by email. No separate practical assessment is described: the hands-on side of your competence is assessed through your documented experience and project sheets, not at the testing center.
| Exam Feature | CIES Detail |
|---|---|
| Questions | 120 multiple-choice, at least four options each |
| Time | Three hours |
| Open or closed book | Closed book |
| Passing score | 75% (Modified Angoff) |
| Delivery | Proctored testing center or online with video proctoring |
| Results | Electronic, immediately, confirmed by email |
| Practical component | None described |
Test-day logistics
For testing-center delivery, bring two government-issued IDs, including one photo ID. ACAC's current Examinations page asks you to arrive 15 minutes early, while the handbook says 30 minutes. That is an unresolved issuer discrepancy, so arrive at the earlier, longer buffer and avoid the risk entirely.
For online delivery, you supply the computer, an approved webcam and a private location. ACAC specifies at least 2 Mbps upload and download speeds and excludes phones and tablets. Test your setup well before the day.
For more on scoring, see what you need to pass; for scheduling windows, see testing windows and deadlines.
Getting Eligible: Experience, Credits and Project Sheets
Eligibility is the most distinctive feature of the CIES, and the part that separates it from a pure test-prep credential. There are three alternative pathways, each pairing education with years of documented indoor environmental remediation experience:
- Four-year path: a related four-year postsecondary degree, or 30 qualifying college credits, plus four years of documented experience.
- Two-year path: a related two-year degree, or 15 qualifying credits, plus six years of experience.
- Diploma path: a high school diploma or GED plus eight years of experience.
Across all pathways, your experience must cover at least three of the five areas: asbestos, lead, hazardous materials, microbial/allergens, and industrial hygiene/chemicals/toxicology. ACAC requires actual field experience, not classroom time alone. Its FAQ explains which semester-credit subjects qualify.
The four project sheets
You must submit four project sheets, along with 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 emphasis on your own actions is deliberate. A sheet that describes what the company did without isolating your role is the kind of document that draws questions.
For a fuller walkthrough, read our guide to CIES requirements, prerequisites and how to qualify.
Fees, Application Timing and Conflicting Rules
The published fees, in US dollars, are straightforward. The exam costs $100 and certification costs $400, which includes a $100 nonrefundable processing fee. Together that is $500 for the initial two-year term. A retake costs $100 and renewal costs $400. ACAC does not publish a separate member and non-member schedule.
| Item | Fee (USD) |
|---|---|
| Examination | $100 |
| Certification (includes $100 nonrefundable processing fee) | $400 |
| Initial total, two-year term | $500 |
| Exam retake | $100 |
| Renewal | $400 |
Our CIES certification cost breakdown covers the budgeting side in more detail, and the ROI analysis addresses whether the spend pays off.
Where the issuer's own documents disagree
Candidates should know that ACAC's current web page and its handbook do not fully agree on the application process. The current application page specifies online submission, required email verifications, and a six-month window including the examination, with unanimous board approval; the board meets every four to six weeks. The handbook instead gives 90 days and describes notarized forms and employer affidavits. This conflict is unresolved, so confirm the current process directly with ACAC before you submit anything. Plan for the longer six-month timeline until told otherwise.
Certification Versus a State Licensing Exam
One source of confusion is that the CIES exam also appears in a state licensing context. Florida's Department of Business and Professional Regulation has listed the CIES among mold-remediation examinations. We could not retrieve that page directly during our latest check, so treat the listing as indexed information to confirm, not a verified current rule.
The important distinction is this: a licensing-only exam result does not itself confer CIES certification. Passing an approved examination is also only one part of getting a state license. Florida's mold remediator checklist shows separate application, education and experience, fingerprinting and insurance requirements. ACAC certification eligibility and state licensing eligibility are two different tracks with two different rulebooks.
Key Takeaway
Decide up front which goal you are pursuing. If you want the ACAC credential, you need the full experience and project-sheet pathway. If you only need an exam result for a state license, your regulator's rules govern, and that result will not make you a Council-certified Indoor Environmental Supervisor.
How a CIES Differs From Related ACAC Credentials
ACAC's indoor air quality program includes other credentials, and candidates frequently compare the CIES with the Council-certified Microbial Remediation Supervisor (CMRS) and the Council-certified Indoor Environmental Remediator track often referred to by the shorthand CIER. The key difference is scope. The CMRS is a mold-focused credential, while the CIES spans five hazard families. If your work is exclusively mold remediation, a narrower credential may fit better; if you routinely handle asbestos, lead and chemical work alongside microbial projects, the CIES maps more closely to your actual duties.
We did not verify a dedicated search-engine comparison between these credentials, and the experience requirements differ by credential, so check each credential's current ACAC page rather than assuming equivalence. The CIES also asks for evidence across at least three disciplines, which is a higher breadth bar than a single-hazard certification would typically set.
Where the Credential Fits in a Career
The natural audience is remediation supervisors, project managers and field leads at abatement and restoration contractors, environmental consulting firms, and facility operators who oversee hazardous-material work in buildings. The multi-discipline scope is attractive where one supervisor may oversee a job involving asbestos-containing materials, lead paint disturbance and microbial growth at the same time.
On compensation, be skeptical of confident claims. We did not find a reliable salary survey specific to ACAC CIES holders, and we cannot show a causal earnings premium from the credential. What you can reasonably say is qualitative: certification documents supervisory competence, which can matter for bidding, client confidence and regulatory comfort. Our salary analysis and CIES jobs overview discuss this honestly rather than quoting invented figures.
Sequencing Your Preparation Around the Five Domains
Because the domains are unweighted, there is no official highest-value area to prioritize. The better question is where your own experience is thinnest, since the exam tests all five, and your project sheets likely cover only three or four. Here is one way to sequence study around that reality, using the reference list ACAC publishes.
Your weakest regulated domain
- If asbestos or lead is thin in your background, start with 40 CFR 763, 40 CFR 61 Subpart M, 29 CFR 1926.1101, 40 CFR 745 and 29 CFR 1926.62.
- These are dense regulatory texts; give them the most time while your attention is freshest.
Hazardous materials and chemicals
- Work through 29 CFR 1910.120, the mercury sources, and the methamphetamine cleanup guidelines.
- Practice choosing respirators with NIOSH Respirator Selection Logic as a decision process.
Microbial contaminants and allergens
- Review the NYC fungi guidelines for containment and remediation logic, even if mold is your strength.
Timed practice and gap review
- Take full-length timed sets of 120 questions in three hours, then return to missed topics.
For a broader plan, see our CIES study guide, the one-page cheat sheet, and our assessment of how hard the exam is. When you are ready to test yourself, try the CIES practice test.
A note on pass rates: we cannot give you a reliable number. No numerical 2025 or 2026 CIES pass rate was verified. ACAC's 2025 certification activity report shows dashes for applicants and pass ratio, which is not the same as a 0% pass rate, and CIES is omitted from the 2025 exam pass ratio report. The 2024 reports conflict with each other, one showing 2 exams taken and 2 passed, another listing 2 applicants and 0%. With candidate counts this small, neither figure says much. Our pass rate article lays out the data and its limits.
Keeping the Credential Active
Certification is valid for two years. ACAC's current recertification procedures specify 40 recertification credits (RCs) per term: 10 for continued field activity and 30 for professional development. You attest to them and retain evidence in case of audit, and a current photo is requested. Note that this differs from the handbook's general 40 RCs and the program page's reference to 20 professional-development hours annually, so follow the current Recertification Procedures page and confirm if in doubt.
Renewal costs $400, so the true cost of maintaining the credential over time is a recurring line item. Factor that into your decision alongside the initial $500.
Frequently Asked Questions
It stands for Council-certified Indoor Environmental Supervisor, a credential issued by the American Council for Accredited Certification. Other unrelated credentials share the acronym, so make sure any resource you use is about the ACAC credential. See also what CIES stands for.
No. ACAC publishes no mandatory preparation course or minimum training-hour requirement, and it does not develop or administer prep courses. Your core resources are the Candidate Handbook, the study guide and the referenced regulations.
Yes. With a high school diploma or GED, the pathway requires eight years of documented indoor environmental remediation experience, covering at least three of the five areas, plus four project sheets and experience verification.
A retake costs $100. The passing score is 75%, and scores are available electronically immediately, so you will know your result right away and can plan your next attempt.
Not entirely. ACAC's handbook and its current web pages differ on some details, such as application timing and arrival time. Use the current ACAC pages as your primary source, confirm anything that conflicts, and see our overview of CIES certification for related guidance.