U2 US Decommissioning certification Exam latest
update Practice Questions (Original) EXAM 2026–
2027 Latest Update Original Questions & Answers
with Detailed Rationales Graded A+.pdf
1. Per EPA 40 CFR 280.70, temporary closure >12 months requires:
A. Nothing
B. Site assessment if required by agency, or 3/6/12 month inspections
C. Permanent closure immediately
D. Annual tightness only
Answer: B
Rationale: Temporary closure >3 months must have release detection
or empty. >12 months may require site assessment if agency says. After
12 months, must perform permanent closure or complete site
assessment.
2. Permanent closure requires notifying implementing agency how
many days before?
A. Same day
B. 30 days prior notice
C. 1 year
D. No notice
Answer: B
Rationale: 40 CFR 280.71 — 30-day notice before permanent closure or
change-in-service.
3. Before excavation for decommissioning, you must:
A. Start digging
B. Call 811 One-Call to locate utilities + check for energized lines
,C. Only check water
D. Nothing
Answer: B
Rationale: 811 required, OSHA excavation safety, PEI RP1700.
4. Tank must be rendered inert before removal by:
A. Adding more gasoline
B. Inerting with CO2, nitrogen, or dry ice — LEL <10% and O2 <8% or LEL
0%
C. Leaving full
D. Air only
Answer: B
Rationale: API 1604, PEI RP1700 — LEL must be <10% or <20% of LEL
depending on standard, O2 <8% or inert atmosphere. Prevent
explosion.
5. Excavated UST must be labeled with:
A. Nothing
B. "Flammable — Previously contained gasoline — Not safe for food"
C. "Clean"
D. Owner name only
Answer: B
Rationale: PEI RP1700 — Must label former contents, hazard warning.
6. What must be removed from tank before disposal?
A. Nothing
B. All liquids, sludge, residues — triple rinse or cleaning per API
C. Only product
D. Leave sludge
,Answer: B
Rationale: Tank must be cleaned, sludge = hazardous waste.
7. Soil samples for site assessment after removal must be taken:
A. No samples needed
B. Where contamination most likely — beneath tank, piping, fill ports,
dispensers per 40 CFR 280.72
C. Random location 1 mile away
D. Only surface
Answer: B
Rationale: 280.72 requires measurement for contamination where
most likely.
8. If contamination found during closure, you must:
A. Ignore
B. Report suspected/confirmed release within 24 hours and begin
investigation per 280.50-280.52
C. Cover with clean soil
D. Wait 1 year
Answer: B
Rationale: Release reporting mandatory.
9. Temporary closure: tank must be:
A. Left full with no monitoring
B. Empty — less than 1 inch product/water, or release detection
maintained, venting maintained
C. Filled with water
D. No requirement
Answer: B
, Rationale: 40 CFR 280.70 — Empty defined as <1 inch, or maintain
corrosion and release detection.
10. Permanent closure options per EPA:
A. Only removal
B. Removal from ground or closure-in-place with fill — sand, concrete
slurry
C. Only fill with water
D. Leave as is
Answer: B
Rationale: 280.71 — Two approved methods: removal or closure-in-
place.
11. Closure-in-place requires:
A. Nothing
B. Empty, clean, fill with inert solid — sand, concrete slurry, foam — per
PEI
C. Fill with gasoline
D. Leave vent open with product
Answer: B
Rationale: Must be cleaned and filled to prevent collapse/subsidence.
12. Tank excavation — competent person per OSHA 29 CFR 1926
Subpart P must:
A. Not needed
B. Classify soil, inspect trench, determine shoring/sloping, monitor
hazards daily
C. Only watch
D. Drive excavator only
update Practice Questions (Original) EXAM 2026–
2027 Latest Update Original Questions & Answers
with Detailed Rationales Graded A+.pdf
1. Per EPA 40 CFR 280.70, temporary closure >12 months requires:
A. Nothing
B. Site assessment if required by agency, or 3/6/12 month inspections
C. Permanent closure immediately
D. Annual tightness only
Answer: B
Rationale: Temporary closure >3 months must have release detection
or empty. >12 months may require site assessment if agency says. After
12 months, must perform permanent closure or complete site
assessment.
2. Permanent closure requires notifying implementing agency how
many days before?
A. Same day
B. 30 days prior notice
C. 1 year
D. No notice
Answer: B
Rationale: 40 CFR 280.71 — 30-day notice before permanent closure or
change-in-service.
3. Before excavation for decommissioning, you must:
A. Start digging
B. Call 811 One-Call to locate utilities + check for energized lines
,C. Only check water
D. Nothing
Answer: B
Rationale: 811 required, OSHA excavation safety, PEI RP1700.
4. Tank must be rendered inert before removal by:
A. Adding more gasoline
B. Inerting with CO2, nitrogen, or dry ice — LEL <10% and O2 <8% or LEL
0%
C. Leaving full
D. Air only
Answer: B
Rationale: API 1604, PEI RP1700 — LEL must be <10% or <20% of LEL
depending on standard, O2 <8% or inert atmosphere. Prevent
explosion.
5. Excavated UST must be labeled with:
A. Nothing
B. "Flammable — Previously contained gasoline — Not safe for food"
C. "Clean"
D. Owner name only
Answer: B
Rationale: PEI RP1700 — Must label former contents, hazard warning.
6. What must be removed from tank before disposal?
A. Nothing
B. All liquids, sludge, residues — triple rinse or cleaning per API
C. Only product
D. Leave sludge
,Answer: B
Rationale: Tank must be cleaned, sludge = hazardous waste.
7. Soil samples for site assessment after removal must be taken:
A. No samples needed
B. Where contamination most likely — beneath tank, piping, fill ports,
dispensers per 40 CFR 280.72
C. Random location 1 mile away
D. Only surface
Answer: B
Rationale: 280.72 requires measurement for contamination where
most likely.
8. If contamination found during closure, you must:
A. Ignore
B. Report suspected/confirmed release within 24 hours and begin
investigation per 280.50-280.52
C. Cover with clean soil
D. Wait 1 year
Answer: B
Rationale: Release reporting mandatory.
9. Temporary closure: tank must be:
A. Left full with no monitoring
B. Empty — less than 1 inch product/water, or release detection
maintained, venting maintained
C. Filled with water
D. No requirement
Answer: B
, Rationale: 40 CFR 280.70 — Empty defined as <1 inch, or maintain
corrosion and release detection.
10. Permanent closure options per EPA:
A. Only removal
B. Removal from ground or closure-in-place with fill — sand, concrete
slurry
C. Only fill with water
D. Leave as is
Answer: B
Rationale: 280.71 — Two approved methods: removal or closure-in-
place.
11. Closure-in-place requires:
A. Nothing
B. Empty, clean, fill with inert solid — sand, concrete slurry, foam — per
PEI
C. Fill with gasoline
D. Leave vent open with product
Answer: B
Rationale: Must be cleaned and filled to prevent collapse/subsidence.
12. Tank excavation — competent person per OSHA 29 CFR 1926
Subpart P must:
A. Not needed
B. Classify soil, inspect trench, determine shoring/sloping, monitor
hazards daily
C. Only watch
D. Drive excavator only
