WA UST Site Assessor Exam UPDATED
ACTUAL Questions and CORRECT
Answers
What is the hold time for soil and preserved GW GRO samples? - CORRECT ANSWER -
14 days
Is an ICC certification needed to install an AST? - CORRECT ANSWER - No
Flammability limits of gasoline - CORRECT ANSWER - 1.4 to 7.6%
How many days do you have from a tank closure to report/provide the UST checklist to ECY? -
CORRECT ANSWER - 30 days
MTCA Method A lead CUL, soil - CORRECT ANSWER - 250 mg/kg
MTCA Method A lead CUL, GW - CORRECT ANSWER - 15 ug/L
Is the vadose zone saturated or unsaturated? - CORRECT ANSWER - Unsaturated
List in order of most mobile to least mobile: Bunker C, heating oil, diesel, gasoline - CORRECT
ANSWER - Gasoline, diesel, heating oil, Bunker C
Is oxygenated gasoline more or less likely to dissolve in water? - CORRECT ANSWER -
More likely; fuel additives like MTBE are more soluble than gasoline
Where to sample on dispenser? - CORRECT ANSWER - 2 feet below where the piping
enters the UST
, Where to sample along piping? - CORRECT ANSWER - Every 50 linear feet and along
joints/elbows
How many GW samples are needed after decommissioning if a release to GW is confirmed, and
where relative to the tank? - CORRECT ANSWER - 3; 1 upgradient, 2 downgradient
What vapor is an FID used to measure? - CORRECT ANSWER - Methane
What is a PID measuring? - CORRECT ANSWER - Mixture of all volatiles
What conditions might impede a PID? - CORRECT ANSWER - Moisture/humidity, dust,
transformers, power lines
What UST capacity does not require a site assessment at closure? - CORRECT
ANSWER - Less than 110 gallons
Purpose of a site check - CORRECT ANSWER - To investigate a UST site for the
presence of a release when evidence indicated that a release may have occurred
Purpose of a site assessment - CORRECT ANSWER - To investigate a UST site at the
time of closure or change-in-service to determine if a release has occurred
Site check vs. site assessment - CORRECT ANSWER - A site check is an investigation of
a UST site for a release when evidence indicates that one many have occurred; a site assessment
determines if a release has occurred
If a confirmed release is identified and reported within 24 hours, what is and is not required? -
CORRECT ANSWER - A site assessment is not required; a site characterization is
required
ACTUAL Questions and CORRECT
Answers
What is the hold time for soil and preserved GW GRO samples? - CORRECT ANSWER -
14 days
Is an ICC certification needed to install an AST? - CORRECT ANSWER - No
Flammability limits of gasoline - CORRECT ANSWER - 1.4 to 7.6%
How many days do you have from a tank closure to report/provide the UST checklist to ECY? -
CORRECT ANSWER - 30 days
MTCA Method A lead CUL, soil - CORRECT ANSWER - 250 mg/kg
MTCA Method A lead CUL, GW - CORRECT ANSWER - 15 ug/L
Is the vadose zone saturated or unsaturated? - CORRECT ANSWER - Unsaturated
List in order of most mobile to least mobile: Bunker C, heating oil, diesel, gasoline - CORRECT
ANSWER - Gasoline, diesel, heating oil, Bunker C
Is oxygenated gasoline more or less likely to dissolve in water? - CORRECT ANSWER -
More likely; fuel additives like MTBE are more soluble than gasoline
Where to sample on dispenser? - CORRECT ANSWER - 2 feet below where the piping
enters the UST
, Where to sample along piping? - CORRECT ANSWER - Every 50 linear feet and along
joints/elbows
How many GW samples are needed after decommissioning if a release to GW is confirmed, and
where relative to the tank? - CORRECT ANSWER - 3; 1 upgradient, 2 downgradient
What vapor is an FID used to measure? - CORRECT ANSWER - Methane
What is a PID measuring? - CORRECT ANSWER - Mixture of all volatiles
What conditions might impede a PID? - CORRECT ANSWER - Moisture/humidity, dust,
transformers, power lines
What UST capacity does not require a site assessment at closure? - CORRECT
ANSWER - Less than 110 gallons
Purpose of a site check - CORRECT ANSWER - To investigate a UST site for the
presence of a release when evidence indicated that a release may have occurred
Purpose of a site assessment - CORRECT ANSWER - To investigate a UST site at the
time of closure or change-in-service to determine if a release has occurred
Site check vs. site assessment - CORRECT ANSWER - A site check is an investigation of
a UST site for a release when evidence indicates that one many have occurred; a site assessment
determines if a release has occurred
If a confirmed release is identified and reported within 24 hours, what is and is not required? -
CORRECT ANSWER - A site assessment is not required; a site characterization is
required
