Minnesota Underground Storage Tank
Closure Contractor Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of properly closing an underground
storage tank (UST)?
A. To increase fuel sales
B. To reduce excavation costs
C. To prevent environmental contamination and safety hazards
D. To avoid property taxes
Answer: C. To prevent environmental contamination and safety hazards
Rationale: Proper closure eliminates risks associated with leaks, residual
product, vapors, and contamination that can impact soil, groundwater,
and public safety.
, 2. Before beginning a UST closure project, the contractor should first:
A. Remove all piping
B. Fill the tank with water
C. Review regulatory requirements and obtain necessary permits
D. Excavate the site
Answer: C. Review regulatory requirements and obtain necessary permits
Rationale: Regulatory compliance and permitting are required before
closure activities begin to ensure environmental and safety standards are
met.
3. Which federal agency establishes UST regulations?
A. OSHA
B. DOT
C. FEMA
D. EPA
Answer: D. EPA
Rationale: The Environmental Protection Agency establishes federal
standards governing underground storage tanks and releases.
4. What is typically required before tank removal?
,A. Painting the tank exterior
B. Installing new piping
C. Emptying and cleaning the tank
D. Replacing dispensers
Answer: C. Emptying and cleaning the tank
Rationale: Tanks must be emptied and cleaned to remove product residues
and reduce fire, explosion, and contamination risks.
5. A combustible gas indicator is primarily used to:
A. Measure soil density
B. Detect groundwater depth
C. Measure flammable vapor concentrations
D. Determine tank thickness
Answer: C. Measure flammable vapor concentrations
Rationale: Gas indicators help determine whether vapor concentrations
present fire or explosion hazards.
6. Which hazard is most associated with residual petroleum vapors in a
tank?
A. Corrosion
B. Flooding
, C. Explosion
D. Freezing
Answer: C. Explosion
Rationale: Petroleum vapors can ignite when exposed to ignition sources,
creating a significant explosion risk.
7. Soil samples collected during closure are primarily used to:
A. Determine property value
B. Evaluate excavation equipment
C. Assess potential contamination
D. Verify tank dimensions
Answer: C. Assess potential contamination
Rationale: Soil sampling helps identify whether a release has occurred and
whether remediation is necessary.
8. What is the purpose of a site assessment during closure?
A. Increase tank capacity
B. Determine fuel pricing
C. Evaluate environmental conditions and possible releases
D. Design a new building
Answer: C. Evaluate environmental conditions and possible releases
Closure Contractor Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of properly closing an underground
storage tank (UST)?
A. To increase fuel sales
B. To reduce excavation costs
C. To prevent environmental contamination and safety hazards
D. To avoid property taxes
Answer: C. To prevent environmental contamination and safety hazards
Rationale: Proper closure eliminates risks associated with leaks, residual
product, vapors, and contamination that can impact soil, groundwater,
and public safety.
, 2. Before beginning a UST closure project, the contractor should first:
A. Remove all piping
B. Fill the tank with water
C. Review regulatory requirements and obtain necessary permits
D. Excavate the site
Answer: C. Review regulatory requirements and obtain necessary permits
Rationale: Regulatory compliance and permitting are required before
closure activities begin to ensure environmental and safety standards are
met.
3. Which federal agency establishes UST regulations?
A. OSHA
B. DOT
C. FEMA
D. EPA
Answer: D. EPA
Rationale: The Environmental Protection Agency establishes federal
standards governing underground storage tanks and releases.
4. What is typically required before tank removal?
,A. Painting the tank exterior
B. Installing new piping
C. Emptying and cleaning the tank
D. Replacing dispensers
Answer: C. Emptying and cleaning the tank
Rationale: Tanks must be emptied and cleaned to remove product residues
and reduce fire, explosion, and contamination risks.
5. A combustible gas indicator is primarily used to:
A. Measure soil density
B. Detect groundwater depth
C. Measure flammable vapor concentrations
D. Determine tank thickness
Answer: C. Measure flammable vapor concentrations
Rationale: Gas indicators help determine whether vapor concentrations
present fire or explosion hazards.
6. Which hazard is most associated with residual petroleum vapors in a
tank?
A. Corrosion
B. Flooding
, C. Explosion
D. Freezing
Answer: C. Explosion
Rationale: Petroleum vapors can ignite when exposed to ignition sources,
creating a significant explosion risk.
7. Soil samples collected during closure are primarily used to:
A. Determine property value
B. Evaluate excavation equipment
C. Assess potential contamination
D. Verify tank dimensions
Answer: C. Assess potential contamination
Rationale: Soil sampling helps identify whether a release has occurred and
whether remediation is necessary.
8. What is the purpose of a site assessment during closure?
A. Increase tank capacity
B. Determine fuel pricing
C. Evaluate environmental conditions and possible releases
D. Design a new building
Answer: C. Evaluate environmental conditions and possible releases
