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I

n 1988, the Coast Guard implemented chemical testing to discourage drug and alcohol use by commercial vessel personnel, reduce the potential for marine 

casualties related to drug and alcohol use, and enhance 

the safety of the maritime transportation industry. While 

the Coast Guard has been collecting data on drug testing 

results for more than 20 years, there have not been any 

studies on the effectiveness of chemical testing in meeting stated goals. 

To determine the extent chemical testing achieves 

these goals, Post-Accident drug and alcohol test results 

of crewmembers from two vessel categories were compared. The fi rst vessel category consists of minimally 

regulated commercial fi shing vessels (CFVs) with no 

crewmember chemical testing requirements except for 

Post-Accident drugs and alcohol. The second category 

consists of highly regulated small passenger vessels 

(SPVs) of 100 tons or less with comprehensive crewmember chemical testing requirements. The drug test 

results that marine employers submit to the Coast Guard 

each year, 2003-2011, were also compared. 

Comparing Post-Accident drug and alcohol positivity 

rates between crewmembers of the above vessel categories, Post-Accident drug and alcohol positive tests per 

serious marine incident (SMI) between crewmembers 

of each vessel category, and Random versus Post-Accident drug test positivity rates from all commercial vessel personnel subject to comprehensive chemical testing 

as reported by their employers, crewmembers on small 

passenger vessels were found to have had much lower 

Post-Accident drug and alcohol positive test results than 

crewmembers on commercial fi shing vessels. Chemical drug and alcohol testing therefore appears to have 

achieved its goals at least to the extent of the data analyzed in this study. 

Methods 

U.S. Documented small passenger vessel (SPV) crewmembers in safety sensitive positions are subject to 

chemical testing as well as credentialing or licensing requirements. SPVs are also subject to inspection and are 

the most regulated of all U.S. Documented vessels. Conversely, U.S. Documented commercial fi shing vessels 

(CFVs) are subject to the least amount of Coast Guard 

regulation. For example, they are subject to safety inspections such as fi refi ghting and lifesaving equipment, 

but are not subject to vessel inspection. CFV crewmembers are not subject to Coast Guard credentialing or licensing requirements; they have no limits on the time 

they are on duty; and, they are not required to pass a PreEmployment chemical test or be subject to subsequent 

Random or Reasonable Cause testing. They are, however, subject to Post-Accident drug and alcohol testing 

so they present a perfect contrast to SPV crewmembers 

for comparison. 

To determine if the test results between the two vessel 

types were statistically signifi cant; the two-proportion 

z-test was used. Yearly and total, overall differences in 

positivity rates and positive tests per SMI between CFVs 

and SPVs were compared. The level of signifi cance used 

for those tests was equal to or less than 0.05, giving less 

than 5% likelihood the results were due to chance. Linear regression and correlation were used to examine the 

relationship between Post-Accident drug test positivity 

rates and Random drug test positivity rates from all vessels with crewmembers subject to chemical testing. 

CFV vs. SPV Post-Accident Positive drug tests

To determine the extent chemical testing has discouraged drug use by commercial vessel personnel, Figure 

1 compares Post-Accident verifi ed positives for one or 

more drugs between CFVs and SPVs from 2003-2011. 

Each year, the positivity rates of CFVs are higher than 

the positivity rates of SPVs by at least 32% and as much 

as 96%. SPV crewmembers averaged 77% fewer positive drug tests than CFV crewmembers. Overall, the 

probability that Post-Accident drug test positivity rates 

between CFV crewmembers and SPV crewmembers 

was due to chance is much less than fi ve percent and 

thus statistically signifi cant. 

CFV vs. SPV Post-Accident alcohol tests

Figure 2 compares Post-Accident alcohol test positivity rates between CFV and SPV crewmembers. Despite 

some expected year to year variation, all of the PostAccident alcohol test positivity rates of SPVs were lower than CFVs by at least 14% and as much as 100%. 

SPV crewmembers averaged 73% fewer positive alcohol 

tests than CFV crewmembers. Overall, the probability 

that Post-Accident alcohol test positivity rates between 

Regulatory

USCG TESTING R Why We Test for Drugs & Alcohol

Is chemical drug and alcohol testing of commercial vessel personnel effective? By Walter J. Brudzinski
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CFV crewmembers and SPV crewmembers was due to 

chance is less than 5 percent and thus statistically significant. 

CFVs vs. ALL vessels Post-Accident drug tests

Figure 3 compares Post-Accident verified positives 

for one or more drugs between CFVs and ALL vessels 

with crewmembers subject to comprehensive chemical 

testing from 2003-2011. Recall from Figure 1 that PostAccident drug test positivity rates of SPV crewmembers 

subject to chemical testing were much lower than drug 

test positivity rates of CFV crewmembers not otherwise 

subject to chemical testing. The differences were even 

greater when CFV crewmembers’ positivity rates are 

compared to crewmembers of ALL vessels with crewmembers subject to comprehensive chemical testing. 

Post-Accident positivity rates of crewmembers subject 

to chemical testing from ALL vessels were at least 89% 

lower and as much as 97% lower than Post-Accident 

positivity rates of CFV crewmembers. Crewmembers 

from ALL vessels averaged 92% fewer Post-Accident 

positive drug tests than CFV crewmembers. Overall, 

the probability that Post-Accident drug test positivity 

rates between CFV crewmembers and ALL crewmembers was due to chance is much less than five percent 

and thus statistically significant. 

CFV vs. SPV Post-Accident positive drug tests per 

SMI 

In response to whether chemical testing reduces the 

potential for marine casualties related to drug and alcohol use, Post-Accident positive drug tests wee compared to the yearly 2003-2011 SMIs in which drug tests 

are reported. Comparisons were performed in the same 

manner as those presented above except they are perincident instead of per-person and include only SMIs 

in which drug tests are reported. As shown in Figure 

4, SPV Post-Accident positive drug tests per SMI are 

much lower than CFV Post-Accident positive drug tests 

per SMI by at least 17% and as much as 93%. SPVs 

Post-Accident positive drug tests per SMI averaged 64% 

lower than CFV Post-Accident positive drug tests per 

SMI. Overall, the probability that the differences between SPV and CFV Post-Accident positive drug tests 

per SMI was due to chance is much less than five percent and thus statistically significant. 

CFV vs. SPV Post-Accident alcohol tests per SMI 

In further response to whether chemical testing re-
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duces the potential for marine casualties related to drug 

and alcohol use, Post-Accident positive alcohol tests 

were compared to the yearly 2003-2011 SMIs in which 

alcohol tests were reported. As shown in Figure 5, SPV 

positive alcohol tests per SMI were much lower than 

CFV positive alcohol tests per SMI by at least 8% and as 

much as 100%. SPV Post-Accident positive alcohol tests 

per SMI averaged 73% lower than CFV Post-Accident 

positive alcohol tests per SMI. 

As with year to year variations in alcohol test results in 

previous comparisons, similar variations exist here. Two 

factors are known to contribute to these variations. The 

first factor is the two hour time period in which alcohol 

tests must be ordered. This time limitation will leave out 

many instances in which tests ought to have been ordered but were not due to the remoteness of the vessel’s 

location, especially commercial fishing vessels that ordinarily operate farther offshore than small passenger vessels. The second factor is the relatively small number of 

tests which could cause wide swings in the percentages 

of positive tests per serious marine incident. Even with 

these factors, the ratio of positive alcohol tests per serious marine incident consistently shows crewmembers 

of small passenger vessels test positive for alcohol less 

than crewmembers of commercial fishing vessels. Overall, the probability that the differences between SPV and 

CFV Post-Accident positive alcohol tests per SMI was 

due to chance is much less than five percent and thus 

statistically significant. 

Random vs. Post-Accident drug test positivity rates

Figure 6 shows yearly 2003-2011Pre-Employment, 

Random, and Post-Accident Random drug test positivity rates from ALL vessels with crewmembers subject to 

chemical testing as reported by their employers. 

Trend Line of Random and Post-Accident positivity 

rates

Crewmembers not passing a Pre-Employment chemical test for dangerous drugs are not hired and thus not 

subject to further comprehensive chemical testing. PreEmployment positivity rates therefore do not directly affect Random or Post-Accident positivity rates; however, 

the differences in positivity rates between Pre-Employment and Random as well as between Pre-Employment 

and Post-Accident are startling. The data appear to show 

the Pre-Employment drug test eliminates those persons 

whose drug use would appear to be so much a part of 

their lives that they are unable to suspend it sufficiently long enough to pass a drug test even with advance 

USCG TESTING
notice. Random and Post-Accident positivity rates also 

appear to have a gradually decreasing trend as shown 

graphically in Figure 7. 

Scatter Plot and Regression line for Random 

versus Post-Accident positivity rates

Examining annual drug test results marine employers 

submit to the Coast Guard, random drug test results represent at least 53% and as much as 63.6% of crewmembers eligible for testing. This represents more than a 

mere sampling of crewmembers subject to Random drug 

tests; therefore, the trend as shown in Figure 7 is fairly 

representative of the crewmember population. Figure 8 

shows Random and Post-Accident positivity rates in a 

scatter plot with a regression line. 

The scatter plot and regression line show that within 

the range of values for which there is data (2003-2011), 

there is a very straight linear relationship between Random and Post-Accident positivity rates. Statistically, 

this linear relationship has a near perfect correlation coefficient of 0.9464. Beyond the shown data points, the 

line may no longer be linear and no predictions are made 

of Post-Accident positivity rates based on Random positivity rates that are not part of the data. It is sufficient to 

conclude that decreasing Random positivity rates have, 

on the average, predicted decreasing Post-Accident positivity rates at least from 2003-2011. On vessels where 

comprehensive chemical testing is required, lower Random positivity rates result in fewer serious marine incidents with drug involvement, thereby enhancing the 

safety of the maritime transportation industry. 

Conclusion

Chemical testing appears to have discouraged drug 

and alcohol use. Analysis of 2003-2011 Post-Accident 

data showed positivity rates from small passenger vessel 

crewmembers subject to comprehensive chemical testing to be significantly lower than those from commercial 

fishing vessels not subject to comprehensive chemical 

testing. Put another way, there is less likely to be drug 

and alcohol use in the more highly regulated segments 

of the maritime industry. Further, chemical testing also 

appears to have reduced the potential for marine casualties related to drug and alcohol use. Again, the 2003-

2011 data showed the SPV group had significantly fewer 

Post-Accident positive drug and alcohol tests per SMI 

than CFVs. Finally, chemical testing appears to have enhanced the safety of the maritime transportation industry. The 2003-2011 data showed Random positivity rates 

are fairly accurate predictors of Post-Accident positivity 

rates among those vessels with comprehensive drug testing requirements. 

NOTES:

This article is a summary of the dissertation submitted 

in partial fulfillment of requirements for a Ph.D. in Judicial Studies. Entitled Chemical Testing of Commercial 

Vessel Personnel: An Analysis of Archived Test Results, 

the views are those of the author and do not necessarily 

reflect the views of DHS, the Coast Guard or its leadership, or the Office of Chief Administrative Law Judge. 

The author expresses appreciation to Captain David S. 

Fish, Chief, Office of Investigations and Casualty Analysis and his staff for their suggestions and assistance, especially Mr. David H. Dickey and Mr. Robert C. Schoening. Mr. Dickey also served on the author’s dissertation 

committee as subject matter expert. 

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Walter J. Brudzinski is Chief 

Administrative Law Judge, U.S. Coast 

Guard. B.A. University of Maryland; 

J.D. George Mason University (with 

distinction); Master’s and Ph.D. in Judicial 

Studies, University of Nevada.