- What the Credential Actually Is
- Who Issues It and Who Stands Behind It
- The Five Competency Areas
- How the Exam Works
- Eligibility and the Four Project Sheets
- Fees, Timeline and Application Mechanics
- The Reference Library Behind the Exam
- Sequencing Your Preparation
- Pass Rate, Salary and Job-Market Reality
- Keeping the Credential: Two-Year Renewal
- Frequently Asked Questions
- CIER here means Council-certified Indoor Environmental Remediator, issued by ACAC's CIER Certification Board and accredited by CESB.
- The exam is 100 multiple-choice questions in three hours, closed book, with a 75% passing score.
- Initial certification costs $500 for a two-year term: a $100 exam fee plus a $400 certification fee.
- You need documented field experience in at least two of five areas, plus four project sheets.
What the Credential Actually Is
The Council-certified Indoor Environmental Remediator credential is a professional certification for people who carry out remediation work inside buildings: removing, containing, cleaning and verifying the clearance of contaminants that threaten occupants and workers. It is not a license, and it is not a short training-course certificate. It is a peer-reviewed, experience-based designation. You qualify by documenting real field work, defending it through project sheets, and then passing a written examination.
If you have seen the acronym elsewhere and wondered whether it refers to something else, this article is strictly about the ACAC credential. The designation covers remediation of asbestos, lead, hazardous materials, microbial contaminants and allergens, and chemicals. That breadth is what distinguishes it from a single-discipline credential: a CIER candidate is expected to understand how engineering controls, cleaning and removal methods, worker safety and regulations apply across several contaminant families.
For shorter definitional explainers, see our companion pages on what CIER is, what CIER stands for and the meaning of the CIER designation. This guide goes further into how the certification works in practice.
Who Issues It and Who Stands Behind It
The credential is issued by the American Council for Accredited Certification (ACAC) through its CIER Certification Board. The program is accredited by the Council for Engineering and Scientific Specialty Boards (CESB), which matters because third-party accreditation signals that the certification process, including exam development, meets recognized standards for professional credentialing.
Exam intelligence and delivery details trace to Kryterion, Inc. The passing standard was set using the Modified Angoff method, a criterion-referenced approach in which subject-matter experts judge how a minimally competent candidate would perform on each question. In practical terms, the 75% cut score reflects a competence standard, not a curve against other test-takers.
The Five Competency Areas
ACAC's Candidate Handbook publishes five competency headings that serve as the backbone of preparation. An important caveat: these are unweighted issuer competencies. No public domain chart or percentage weights have been verified, and the handbook's own study guide warns that its selected pages are examples rather than exhaustive coverage. Treat the five headings as your minimum map, not a guarantee of what every question will touch. Each competency addresses engineering controls, cleaning and removal methods, worker safety and applicable regulations.
Domain 1: Understand and execute successful remediation of asbestos in the indoor environment
Asbestos work is among the most heavily regulated remediation activities, so expect regulation-driven questions.
- Federal asbestos rules in 40 CFR 763 and the NESHAP requirements in 40 CFR 61 Subpart M
- The OSHA construction standard at 29 CFR 1926.1101, including work practices and worker protection
- Containment, negative-pressure enclosures, wet methods and waste handling
Domain 2: Understand and execute successful remediation of lead in the indoor environment
Lead remediation questions blend occupant protection with worker exposure control.
- The EPA lead rule in 40 CFR 745 and OSHA's lead-in-construction standard at 29 CFR 1926.62
- Dust control, cleaning and clearance concepts for lead-contaminated surfaces
- Worker exposure, respiratory protection and hygiene practices
Domain 3: Understand and execute successful remediation of hazardous materials in the indoor environment
This is the broadest and least predictable area, because "hazardous materials" spans many contaminant types.
- Hazardous waste operations and emergency response requirements under 29 CFR 1910.120
- Mercury response, a topic where the issuer's reference descriptions are inconsistent (covered below)
- Methamphetamine laboratory cleanup, per the EPA's voluntary guidelines
Domain 4: Understand and execute successful remediation of microbial contaminants and allergens in the indoor environment
Mold and biological contamination require both remediation technique and judgment about scope and containment.
- The New York City Department of Health and Mental Hygiene guidelines on assessment and remediation of fungi in indoor environments (2008)
- Moisture source correction, containment levels and cleaning methods
- Respiratory protection selection, drawing on NIOSH Respirator Selection Logic (2004)
Domain 5: Understand and execute successful remediation of chemicals in the indoor environment
This area connects to the industrial hygiene, chemicals and toxicology experience category that candidates may use to qualify.
- Chemical hazard recognition, exposure pathways and basic toxicology concepts
- Engineering controls, ventilation and decontamination approaches
- Worker safety requirements and the regulatory framework that governs chemical exposure
For a deeper treatment of each area, read our complete guide to all five CIER content areas. One wording note: the CERT-published competency list contains five headings, but because no official exam blueprint chart is public, that count should not be mistaken for a verified official exam-domain count.
How the Exam Works
| Feature | CIER Detail |
|---|---|
| Question count | 100 multiple-choice questions, each with at least four answer options |
| Time allowed | Three hours |
| Delivery | Computer-delivered written examination |
| Reference materials | Closed book |
| Passing score | 75%, set by the Modified Angoff method |
| Practical component | No separate practical assessment described |
| Scored vs. unscored split | Not published |
| Results | Available electronically immediately, confirmed by email |
Three hours for 100 questions works out to roughly 108 seconds per item on average, which is comfortable if you know the material and punishing if you are reconstructing regulations from scratch. The handbook describes a fixed question set with randomized question and answer order, so you will not see a fixed sequence of questions memorized from someone else's recollection. Adaptive testing is not described, and calculator permission is unverified, so check the current candidate instructions before exam day rather than assuming.
Testing center or online proctoring
Candidates can test at a testing center or through online video proctoring. For the online route, you need your own computer, an approved webcam, a private location, and at least 2 Mbps upload and download speed. Phones and tablets are excluded. At a testing center, expect to present two government-issued IDs, one of which must be a photo ID.
To judge whether the format suits you, see our difficulty guide to the CIER exam and the specifics in what the CIER passing score means.
Eligibility and the Four Project Sheets
Because the CIER is experience-based, eligibility is where many candidates spend most of their effort. There are two qualifying paths:
- Education path: a related two-year postsecondary degree, or 15 qualifying college credits, plus at least one year of documented indoor environmental remediation experience.
- Experience path: a high school diploma or GED plus two years of documented experience.
Experience must cover at least two of five areas: Asbestos; Lead; Hazardous Materials; Microbial/Allergens; and IH/Chemicals/Toxicology. That breadth requirement is deliberate. A technician who has only ever done mold work cannot qualify on that alone. You need documented exposure to a second discipline.
What the project sheets demand
Candidates submit four project sheets, along with applicable educational evidence and experience verification. ACAC's FAQ requires actual field experience and describes each sheet as having three components: the problem, your own responsibilities and actions, and the outcome. The emphasis on "your own" is critical. A sheet that describes what the crew or company did, without isolating your role, is weaker than one that clearly states what you personally decided, supervised or executed.
Key Takeaway
Choose project sheets that collectively demonstrate breadth across at least two of the five experience areas, and write each around a clear problem, your specific actions and a measurable outcome such as passed clearance or resolved exposure issue.
No mandatory preparation course and no minimum training-hour requirement is published. ACAC does not develop or administer preparation courses. A separate independent-referee count could not be verified, so rely on the current application page for the verification steps you must complete. Our full walkthrough is in CIER requirements: eligibility, prerequisites and how to qualify.
Fees, Timeline and Application Mechanics
| Item | Amount (USD) |
|---|---|
| Examination fee | $100 |
| Certification fee (includes a $100 nonrefundable processing fee) | $400 |
| Total for initial two-year term | $500 |
| Retake | $100 |
| Renewal | $400 |
No separate member versus non-member fee schedule is published. The authoritative source is ACAC's Fees and Payments page. For a fuller cost analysis including indirect expenses, see the CIER certification cost breakdown.
Submission and approval
ACAC's current application page specifies online submission, required email verifications, and unanimous board approval. It gives you six months to finish the process including the exam, and says the board meets every four to six weeks. Build that board-meeting cadence into your plan: an application submitted just after a meeting may wait weeks for review.
For scheduling guidance, see CIER exam dates, deadlines and scheduling.
The Reference Library Behind the Exam
ACAC's published study materials read like a regulatory bookshelf, which tells you something about the exam's character: it tests whether you know what the rules require and how remediation practice implements them. The listed references include:
- The ACAC Code of Conduct
- 40 CFR 763 (asbestos in schools and related provisions)
- 40 CFR 61 Subpart M (asbestos NESHAP)
- 29 CFR 1926.1101 (OSHA asbestos in construction)
- 40 CFR 745 (lead-based paint rules)
- 29 CFR 1926.62 (OSHA lead in construction)
- 29 CFR 1910.120 (hazardous waste operations and emergency response)
- NYC Department of Health and Mental Hygiene, Guidelines on Assessment and Remediation of Fungi in Indoor Environments (2008)
- NIOSH Respirator Selection Logic (2004)
- Mercury-response material
- EPA Voluntary Guidelines for Methamphetamine Laboratory Cleanup
Two cautions deserve attention. First, the issuer's materials describe the mercury reference inconsistently: the reference list points to EPA Region 5 material (section 5), while the study-guide detail points to the National Elemental Mercury Response Guidebook (section 9.4). Study the mercury topic from both so you are covered either way. Second, publication dates on these references are not exam-version dates; a 2004 or 2008 document may still be a current exam source. The public study guide itself advises comprehensive study of the references rather than relying on its sample pages.
Also be skeptical of third-party materials. Public listings for CIER prep content exist on document-sharing and marketplace sites, but their completeness, answer accuracy and alignment to the references above are unverified. A useful test of any prep product: does it tie questions back to the specific regulations listed here, and does it cover all five competencies, not just one or two? Our CIER study guide lays out a reference-by-reference approach, and the CIER cheat sheet condenses the must-know facts for last-pass review.
Sequencing Your Preparation
Rather than a generic schedule, sequence your study by where your experience is thinnest. Because eligibility only requires two of the five areas, most candidates enter the exam strong in two disciplines and comparatively weak in the others. A sensible order puts your weakest regulation-heavy area first, while you are fresh.
Regulation-dense domains you have not worked in
- If asbestos is new to you, start with 40 CFR 763, 40 CFR 61 Subpart M and 29 CFR 1926.1101
- If lead is new, pair 40 CFR 745 with 29 CFR 1926.62
Hazardous materials and chemicals
- Work through 29 CFR 1910.120, mercury response and meth-lab cleanup guidance
- Review toxicology and exposure basics tied to Domain 5
Microbial work and respiratory protection
- Study the NYC fungi guidelines and NIOSH respirator selection logic
- Then take timed practice sets across all five areas
Because the exam is closed book, treat the final stretch as retrieval practice under the three-hour limit. You can run timed sets on our CIER practice test to see whether you are averaging well under the roughly 108 seconds available per question.
Pass Rate, Salary and Job-Market Reality
Candidates naturally want to know how many people pass and what the credential earns. Here the honest answer is that the public record is thin.
What the pass-rate data does and does not say
A numerical CIER pass rate is not publicly disclosed in the retrieved reports. ACAC's Accredited Certification Activity report as of December 31, 2025 shows dashes for applicants, pass ratio and recertifications, with 0 current certifications listed, and CIER is absent from ACAC's 2025 Exam Pass Ratio report. A dash is not a 0% pass rate. Likewise, these issuer counts do not establish that the credential has been discontinued, and they do not tell you how demand or difficulty compares with other credentials. No 2026 rate has been verified. Our CIER pass rate analysis explains how to read these reports without over-interpreting them.
Salary and employability
No reliable salary survey specific to ACAC CIER holders was verified, and no causal earnings premium from holding the credential was established. Anyone quoting a precise CIER salary figure is likely borrowing from a different credential or inventing it. What can be said qualitatively: the work sits within environmental remediation, abatement, industrial hygiene support and building-contamination response, and the credential's value is most plausible where employers or clients want documented, multi-discipline competence. Evaluate the investment against your own market using our CIER salary guide and ROI analysis, and browse the kinds of roles in CIER jobs.
Keeping the Credential: Two-Year Renewal
Certification is valid for two years. ACAC's current Recertification Procedures call for 40 recertification credits (RCs): 10 for continued field activity and 30 for professional development during the term. You must attest to them and retain evidence in case of audit, and ACAC requests a current photo. The renewal fee is $400.
Note the documentation conflict: the handbook's general 40-RC wording and the program page's reference to 20 professional-development hours per year differ from the current procedures. Follow the current Recertification Procedures page and keep dated records of every training course, conference or field assignment from day one of your term, not in a scramble before the deadline.
Frequently Asked Questions
It stands for Council-certified Indoor Environmental Remediator, issued by the American Council for Accredited Certification (ACAC) through its CIER Certification Board. For more on the terminology, see what CIER certification is and what CIER means.
The exam has 100 multiple-choice questions with at least four answer options each, delivered by computer over three hours, closed book. The passing score is 75%, set using the Modified Angoff method. The scored versus unscored split is not published.
The initial two-year term totals $500: a $100 examination fee plus a $400 certification fee that includes a $100 nonrefundable processing fee. A retake costs $100 and renewal costs $400.
Not necessarily. You can qualify with a related two-year degree or 15 qualifying credits plus one year of documented experience, or with a high school diploma or GED plus two years. Experience must span at least two of five areas, and you submit four project sheets. No mandatory prep course or training-hour minimum is published.
Yes. ACAC offers testing-center or online video proctoring. Online delivery requires your own computer, an approved webcam, a private location and at least 2 Mbps upload and download speed. Phones and tablets are not allowed. Confirm current logistics with ACAC before scheduling.