1. Dealing with Gasoline and ULSD Cross Drops
Edward W English, II
Vice-President Technical Director
Fuel Quality Services, Inc.

2. What is a Cross Drop?
A Cross Drop occurs when Gasoline(E10) or ULSD is dropped into
a tank containing a ULSD or Gasoline(E10) potentially rendering
the entire tank out of specification.

3. Potential Outcome Possible outcomes of a Cross Drop:
Gasoline (E10) contamination of ULSD or
ULSD contamination Gasoline (E10).
ULSD Contaminated by Gasoline (E10)
Gasoline (E10) Contaminated by ULSD
Minimum quantity 0.5%
Minimum quantity 4-5%
Reduction Flash Point
Poor Cold Start due to Low Volatility
Reduction in Lubricity & Viscosity
Injector Valve Deposits, poor fuel spray
HPCFR / Injector Low Pressure
Residue buildup on cylinder walls
Premature detonation
Lower octane number (knocking)
Diesel fuel could become flammable

4. What to Do, Step 1 “Quarantine and Isolate”
Immediately quarantine and isolate the affected fuel system from use (from fill to dispenser).
Immediately quarantine and isolate affected vehicles.
If a vehicle fuel tank has been filled leave the engine off, do not put key into the ignition to avoid circulating the fuel in the vehicle engine.

5. What to Do, Step 2 “Sample affected fuel systems”
Obtain samples of the fuel storage tank through the dispenser.
Obtain samples of fuel from the affected vehicles
Can perform qualitative tests in-house
Send samples to a lab for quantitative results

6. What to Do, Step 3 “Optional Qualitative Tests”
ULSD Contaminated with Gasoline (E10)
Gasoline (E10) Contaminated with ULSD
Qualitative Test
Smell Test
(Gasoline odor)
(Diesel odor)
Volatility Test (5 drops)
(Evap., rate proportion to gasoline content)
Volatility (5-10 drops)
(After gasoline evaporates, ULSD Residue)
Fuel Shake
(Reduced to nonfoam indicate gasoline)
(Signs of foam indicate ULSD)
Ignition Test - 5 drops on a dish
(Sustained flame indicates gasoline)

7. What to Do, Step 4 “Quantitative Tests”
ULSD Contaminated with Gasoline (E10)
Gasoline (E10) Contaminated with ULSD
Quantitative Test
D93 - Flash Point
(Flash point near or less than 52˚C)
D86 – Distillation (for ULSD >2%)
(IBP ≥ 149˚F / FBP ≥ 437˚F)
GC Finger Print
(Hydrocarbon peaks prior to C10)
D381 – Gum Test (for ULSD >2%)
(Unusual mass wt. “unwashed gums”)
GC Finger Print (for ULSD >2%)
(Hydrocarbon peaks after C10)

8. Example Test Results

9. Gasoline Tests – D381 & D86 Gasoline Samples Lab Number Blinded
Lab Number
Blinded
Sample Code
Site
 Blinded
 Blinded 
  Blinded
D381
UnWshdGum
g/100mL
2085
3914
840.5
1347
WashedGum 1
1.5
0.5
D86
IBP
deg F
98.4
159.5
102.8
104.8
Evap_5
117.9
162.5
124.1
126.7
Evap_10
130
165
132.8
134.3
Evap_15
135.6
197.4
138.4
140.1
Evap_20
141.6
221.2
143.1
144.9
Evap_30
150.1
254.2
150.8
1051.8
Evap_40
198.7
283
196
208.47
Evap_50
243.6
318.2
234.9
249.2
Evap_60
282.9
352.87
275.4
289
Evap_70
338.9
412.3
324.4
344.3
407
486.1
392
413.9
511
559.7
501.6
517.4
568.6
606.1
569.4
574.3
FBP
618.3
639.4
608.4
621.6
Recovered mL
96.2
99.7
96.8
97.4
Residue
0.9
1.6
1.4
Loss
2.3
-0.6
1.2

10. Gasoline Tests – GC Fingerprint
Diesel
Peaks
Gasoline
Gasoline Carbons C5-C10
Diesel Carbons C11-C22
Diesel
Peaks
Gasoline
Gasoline Carbons C5-C10
Diesel Carbons C11-C22

11. Diesel Tests – Flash Point
Diesel Fuel Samples
Lab Number
Blind
Sample Code
D93
Flash
Deg F
< 80
Deg C
< 27

12. Diesel Tests – GC Finger Print
Gasoline
Peaks
Diesel
Peaks
Gasoline Carbons C5-C10
Diesel Carbons C11-C22

13. What to Do, Step 5 “If test results are negative”
If test results do not detect a Cross Drop, it is business as usual.
If you suspect periodic Cross Drops or Cross Contamination implement periodic surveillance and send sample to a reputable laboratory for testing.

14. What to Do, Step 6 “If test results are positive”
Contact all responsible parties of the event and test results
Thoroughly drain and vacuum the affected tank.
Flush the transfer and dispenser lines (remove filter from filter housing).
Replace the dispenser filter.
Fill tank and place back in service.
If vehicles are affected, thoroughly flush and clean vehicle fuel systems.

15. Q&A