Report to the Ranking Minority 

Member, Subcommittee on Aviation, 

Committee on Transportation and 

Infrastructure, House of 

Representatives 

United States General Accounting Office

GAO 

January 2003 AVIATION SAFETY 

Undeclared Air 

Shipments of 

Dangerous Goods and 

DOT’s Enforcement 

Approach 

GAO-03-22 
Little is known about the nature and frequency of undeclared shipments of 

dangerous goods. While major carriers and the Postal Service believe such 

shipments are rare, their belief is based mainly on inspections of problem 

shipments, such as those that leak. Statistically valid, generalizable data are 

not available and would be difficult to obtain, not only because more 

inspections would entail costly delays for carriers but also because 

Constitutional protections limit DOT’s and the Postal Service’s inspection 

authority. DOT is seeking greater authority to open potentially problematic 

shipments for inspection, but its efforts are not limited to air transport and 

would not enable DOT’s Federal Aviation Administration (FAA) to obtain 

statistically valid, generalizable data on the nature and frequency of 

undeclared air shipments. A change in the law requiring that shippers 

consent to the opening of packages for inspection might be appropriate for 

air transport and would enable FAA to obtain such data. FAA could then 

identify the resources and actions needed to address the problem. 

Federal regulations create a framework for transporting dangerous goods 

safely, and outreach to shippers and carriers helps to prevent undeclared 

shipments. Private industry does business primarily with “known 

shippers” (those that have shown they comply with the regulations). The 

Postal Service cannot restrict its business to known shippers, but it 

requires customers to bring packages weighing 16 ounces or more to a 

post office for screening. Carriers and the Postal Service both train their 

employees to screen for undeclared shipments. 

The Postal Service and FAA monitor and enforce compliance with federal 

regulations for transporting dangerous goods by air. However, the Postal 

Service cannot fine violators and seldom takes criminal action, since most 

violations are inadvertent. FAA’s enforcement guidance calls for 

documenting the reasons for any changes in the fines its inspectors initially 

propose. GAO’s review of enforcement case files indicates that the reasons 

for changes were not always documented. FAA attributes some changes to 

the results of penalty negotiations. Because FAA is not always following its 

guidance, it cannot ensure that its fines are appropriate or consistent. 

Figure 1: Air Transport of Dangerous Goods Authorized by DOT 

•

•

•

May not travel by either passenger or cargo aircraft

Sources: Research and Special Programs Administration, Department of Transportation, and © 1998 Nova Development Corporation. 

May travel by cargo, but 

not by passenger, aircraft

May travel by either passenger or 

cargo aircraft

20%

30%

50%

AVIATION SAFETY

Undeclared Air Shipments of Dangerous 

Goods and DOT’s Enforcement Approach 

www.gao.gov/cgi-bin/getrpt?GAO-03-22.

To view the full report, including the scope 

and methodology, click on the link above. 

For more information, contact Gerald 

Dillingham at (202)-512-2384 or 

dillinghamg@gao.gov. 

Highlights of GAO-03-22, a report to the 

Ranking Minority Member, Subcommittee 

on Aviation, Committee on Transportation 

and Infrastructure, House of 

Representatives 

January 2003 

When shipments of dangerous 

goods (hazardous chemical 

substances that could endanger 

public safety or the environment, 

such as flammable liquids or 

radioactive materials) are not 

properly packaged and labeled for 

air transport, they can pose 

significant threats because there is 

little room for error when 

something goes wrong in flight. To 

better understand the risks posed 

by improper (“undeclared”) air 

shipments, we assessed what is 

known about their nature and 

frequency, what key mechanisms 

are in place to prevent their 

occurrence, and what the 

Department of Transportation 

(DOT) and the Postal Service do to 

enforce federal regulations for 

shipping dangerous goods by air. 

Figure 1 shows how DOT regulates 

the air transport of dangerous 

goods in the United States. 

GAO recommends that DOT 

improve its enforcement approach 

by (1) determining whether the 

unique characteristics of air 

transport warrant the development 

of a legislative proposal that would 

enhance DOT’s authority to inspect 

packages shipped by air and (2) 

requiring FAA to strengthen its 

policy on documenting the reasons 

for changes to the amounts of the 

recommended fines. 
Page i GAO-03-22 Aviation Safety 

Letter 1

Results in Brief 2 

Background 5 

Shipments of Undeclared Dangerous Goods Can Have Serious 

Consequences, but Their Nature and Frequency Are Difficult to 

Estimate 11 

Government and Industry Rely on Several Mechanisms to Prevent 

Dangerous Goods Shipments from Compromising Safety 20 

For DOT, Inadequate Documentation, and for the Postal Service, 

Lack of Civil Penalty Authority Hamper Enforcement of 

Dangerous Goods Regulations 27 

Conclusions 32 

Recommendations for Executive Action 33 

Agency Comments and Our Evaluation 33 

Scope and Methodology 34 

Appendix I FAA’s Dangerous Goods Informational Brochure 

for Passengers 37 

Appendix II Mailability of Dangerous Goods, by DOT Class 38 

Appendix III Data Collected by DOT Agencies on Dangerous 

Goods Incidents and Enforcement Actions 39 

Appendix IV GAO Contacts and Staff Acknowledgments 41 

GAO Contacts 41 

Acknowledgments 41 

Tables 

Table 1: Dangerous Goods Classes and Descriptions 8 

Table 2: DOT Databases Tracking Information on the Air 

Transportation of Dangerous Goods 39 

Contents 
Page ii GAO-03-22 Aviation Safety 

Figures 

Figure 1: Air Transport of Dangerous Goods Authorized by DOT 6 

Figure 2: Dangerous Goods Cargo Containers 7 

Figure 3. FAA’s Dangerous Goods Enforcement Process (for Civil 

Penalty Cases) 30 

Abbreviations 

AAIRS Airport and Air Carrier Information Reporting System 

C.F.R. Code of Federal Regulations 

DOT Department of Transportation 

EIS Enforcement Information System 

FAA Federal Aviation Administration 

GAO General Accounting Office 

HMIRS Hazardous Materials Information Reporting System 

HMR Hazardous Materials Regulations 

RSPA Research and Special Programs Administration 

TSA Transportation Security Administration 

UNISHIP Unified Shipper Enforcement Data System 
Page 1 GAO-03-22 Aviation Safety 

January 10, 2003 

The Honorable William O. Lipinski 

Ranking Minority Member 

Subcommittee on Aviation 

Committee on Transportation and Infrastructure 

House of Representatives 

Dear Mr. Lipinski: 

Each day, businesses, individuals, and government agencies package and 

ship dangerous goods on ships, trains, trucks, and airplanes.1

 Dangerous 

goods are by definition chemical, including infectious, substances (or 

anything containing such substances) that pose a threat to public safety or 

the environment during transportation. When these goods are properly 

packaged, labeled, and stowed onboard, they can be transported safely, 

but when they are not, they can pose significant threats to people and 

property. Improper, or “undeclared,”2

 shipments of dangerous goods are 

particularly dangerous in air transport because there is little room for 

error or time to take corrective action if a problem occurs in flight—a 

lesson learned tragically in 1996 when a ValuJet plane crashed in Florida 

after oxygen generators caught fire in the plane’s cargo compartment. 

To better understand the overall risks that undeclared shipments of 

dangerous goods can pose to aviation safety, we examined the Department 

of Transportation’s (DOT) and the U.S. Postal Service’s monitoring of the 

transportation of dangerous goods by commercial cargo and passenger 

aircraft, although we focused primarily on cargo aircraft. As agreed with 

your office, we addressed three researchable questions: 

 1

The Hazardous Materials Transportation Act, as amended, principally governs the 

transportation of dangerous goods. It is codified at title 49, chapter 51, of the United States 

Code. 

2

We use the term “undeclared” to describe two types of improper shipments of dangerous 

goods: (1) those that a shipper has explicitly denied are hazardous or has not identified as 

hazardous and (2) those that a shipper has identified as hazardous but has otherwise 

misrepresented (for example, the shipper has understated the quantity so that the materials 

can be shipped by passenger aircraft rather than by cargo aircraft). 

United States General Accounting Office

Washington, DC 20548 
Page 2 GAO-03-22 Aviation Safety 

• What do DOT, the Postal Service, and others involved in the commercial 

air transport of dangerous goods know about the nature and frequency of 

undeclared shipments? 

• What are the key mechanisms the federal government and private industry 

have in place to prevent dangerous goods shipments from compromising 

aviation safety? 

• What do DOT and the Postal Service do to enforce federal regulations for 

shipping dangerous goods by air? 

We focused our review primarily on the shipments of dangerous goods 

onboard cargo aircraft, in part, because more types and quantities of 

dangerous goods are permitted on cargo aircraft than on passenger 

aircraft. To address these questions, we analyzed recent reports by DOT 

on its dangerous goods programs and on the threat that carrying such 

goods can pose, particularly when the shipments are undeclared. We 

reviewed research on methods that might be used to estimate the 

frequency of undeclared shipments, and we consulted with both GAO and 

academic experts in these methods. To determine the extent to which 

undeclared shipments may occur, we interviewed officials of four major 

carriers that handle over 60 percent of annual air freight traffic in the 

United States, and we visited the premises of three of these carriers to 

review their procedures for identifying and preventing undeclared 

dangerous goods shipments. We also reviewed the results of a joint effort 

by the Federal Aviation Administration (FAA) and the U.S. Customs 

Service, which has the authority to inspect and search international 

shipments, to detect, among other things, undeclared dangerous goods 

shipments. We interviewed Postal Service, FAA, and other DOT officials 

with various oversight responsibilities for dangerous goods transportation. 

To evaluate FAA’s enforcement strategy, we examined the agency’s 

assessments in 30 cases. These cases were randomly selected to fairly 

represent the full range of over 2,000 cases in the database. While the 

number of cases we tested was too small for us to estimate the extent to 

which FAA’s enforcement strategy was followed in the entire database, 

our examination allowed us to describe the types of practices that occur at 

critical points in the penalty assessment process. Our detailed scope and 

methodology appears at the end of this report. 

DOT, the Postal Service, and major carriers know that undeclared air 

shipments of dangerous goods occur and can have serious consequences, 

but they lack statistically valid, generalizable data to reliably estimate the 

Results in Brief 
Page 3 GAO-03-22 Aviation Safety 

nature and frequency of such shipments, assess their risks, profile 

potential violators, and allocate resources optimally for prevention, 

detection, and correction. DOT researchers have concluded that data are 

not available to reliably estimate the nature and frequency of dangerous 

goods shipments or assess their risks. Carriers maintain that such 

shipments are rare, but their views are based almost entirely on the 

occurrence of incidents—shipments that were opened after a leak, spill, 

odor, or other anomaly suggested a potential problem—rather than on 

information about shipments that gave no cause for opening. 

Technological, economic, and legal hurdles combine to make estimates of 

undeclared dangerous goods shipments difficult. The current less intrusive 

screening equipment is not designed to detect many types of dangerous 

goods, and therefore opening packages is the only reliable means of 

obtaining information on undeclared shipments. While carriers generally 

obtain the consent of shippers to open packages that they accept for 

shipment, they seldom open packages because doing so is too slow and 

costly to be practicable except when incidents occur. Under the Fourth 

Amendment to the Constitution, which prohibits unreasonable searches 

and seizures, DOT may generally not open and inspect packages without a 

search warrant or the shipper’s consent. The Postal Service treats First 

Class or Express mail packages traveling by air as being sealed against 

inspection and protected by the Fourth Amendment. Without the authority 

to open packages for inspection, neither DOT nor the Postal Service is in a 

position to gather data on undeclared shipments of dangerous goods. 

To prevent dangerous goods shipments from compromising safety, the 

federal government relies on regulation, research, and outreach, and 

private industry relies on policies for dealing with “known shippers” (a 

DOT term for shippers that have demonstrated their previous business 

history), other restrictions on customers or the materials they carry, 

training, and sanctions. Federal regulations create a framework for 

transporting dangerous goods safely. If DOT finds that these regulations 

are insufficient to ensure safety, it can sponsor and has sponsored 

research to determine how it should modify the regulations. DOT and the 

Postal Service also provide information to the public on materials that may 

not be shipped by air. Carriers try to prevent dangerous goods shipments 

from compromising safety by dealing preferentially with known shippers. 

In addition, some carriers accept fewer types of dangerous goods for 

shipment than the law allows. While the Postal Service cannot limit its 

business to known shippers, it restricts the materials it accepts for 

shipment and requires shippers to bring packages weighing 16 ounces or 

more to a post office, where employees can ask questions about the 

contents. Carriers, including the Postal Service, also train their employees 
Page 4 GAO-03-22 Aviation Safety 

to be a first line of defense against undeclared shipments. Finally, carriers 

may require shippers to take remedial training or may refuse to do 

business with them if they repeatedly violate the dangerous goods 

regulations. 

To evaluate the effectiveness of and enforce federal regulations for 

shipping dangerous goods by air, DOT collects data on incidents involving 

dangerous goods, monitors shippers’ and carriers’ performance, and 

assesses civil penalties. DOT has the authority to either assess civil 

penalties or seek criminal enforcement action against violators. Within 

DOT, FAA is responsible for enforcing compliance with the regulations for 

shipping dangerous goods by air, while the Transportation Security 

Administration, which is scheduled to be transferred to the new 

Department of Homeland Security, is responsible for the security of cargo 

shipments. To ensure that appropriate civil penalties are assessed, FAA’s 

enforcement guidance requires the agency to consider the compliance 

history of violators across all modes of transportation. This guidance was 

difficult for FAA to follow because most operating administrations were 

not submitting current enforcement data to DOT. DOT has directed its 

operating administrations to submit current enforcement data to a 

centralized database, so that the administrations can obtain current 

information on the compliance history of violators across the modes. To 

ensure that similar cases are treated consistently and fairly, FAA’s 

enforcement guidance also requires the agency to document the reasons 

for any reduction in a recommended civil penalty. Our analysis of FAA’s 

case files indicates that the agency is not always following this policy. We 

are recommending that FAA document its penalty assessments, as 

required, so that it can demonstrate that it is handling similar cases 

consistently. 

The Postal Service also collects data on actual releases of dangerous 

goods being transported, monitors the compliance of shippers and 

carriers, and can seek criminal penalties for violations of its regulations; 

however, it cannot impose civil penalties for such violations. According to 

industry officials, many dangerous goods violations result from ignorance. 

Under such circumstances, the Postal Service maintains, civil penalties 

may be appropriate and would make it easier to recover the sometimes 

substantial costs of cleanup and damages. DOT’s hazardous materials 

reauthorization proposal includes a provision that would allow the Postal 

Service to impose civil penalties. 

This report contains recommendations to DOT that FAA evaluate the need 

for additional inspection authority to obtain statistically valid data on 
Page 5 GAO-03-22 Aviation Safety 

undeclared air shipments of dangerous goods and document its penalty 

assessments, as required, so that it can demonstrate that it is handling 

similar cases consistently. DOT agreed with our recommendations, and 

DOT and the Postal Service generally agreed with the facts in our report. 

Both DOT and the Postal Service provided clarifying and technical 

comments, which we incorporated as appropriate. 

DOT regulates tens of thousands of dangerous goods, which can include 

poisons, pesticides, radioactive materials, and explosives.3

 About 20 

percent of these goods may not travel by air at all. As shown in figure 1, 

the remainder may travel on passenger or cargo aircraft, or both. 

 3

Each time someone ships dangerous goods, the contents of the shipment must be 

identified by using 1 of over 3,400 different shipping names. A shipping name can refer to a 

specific material that DOT has identified as dangerous; it can also be a generic description 

for a material that meets the overall criteria for a dangerous goods class, but for which 

there is not a division (within that class) to more precisely identify it. According to DOT, 

because many materials are identified using the generic descriptions within each class, the 

actual number of dangerous goods is much greater than the 3,400 shipping names that DOT 

spells out. 

Background 
Page 6 GAO-03-22 Aviation Safety 

Figure 1: Air Transport of Dangerous Goods Authorized by DOT 

Using a United Nations classification system, DOT divides all dangerous 

goods into nine general classes according to their physical, chemical, 

biological, and nuclear properties. Most of the dangerous goods that may 

not travel by air at all are the most highly explosive, toxic, oxidizing, selfreactive, or flammable chemical substances or articles in their class. In 

addition to prohibiting some types of dangerous goods from being carried 

by air at all, DOT restricts the types and amounts of other dangerous 

goods that any individual passenger or cargo aircraft may carry. For both 

passenger and cargo aircraft, DOT spells out these restrictions in four 

ways: 

• By name—dangerous goods that represent an unacceptable hazard on 

aircraft or are known to have caused an aircraft fire or explosion, such as 

chemical oxygen generators, are specifically forbidden by name. 

• By hazard class and subdivision—certain subdivisions of the classes of 

dangerous goods are known to be highly reactive or toxic (for example, 

most explosives and all spontaneously combustible materials), so DOT 

excludes them from passenger flights. 

•

% •

•

May not travel

by either 

passenger or 

cargo aircraft

May travel by 

cargo, but not 

by passenger, 

aircraft

May travel 

by either 

passenger or 

cargo aircraft

20%

30

50%

Sources: Research and Special Programs Administration, Department of Transportation, and © 1998 Nova Development Corporation. 
Page 7 GAO-03-22 Aviation Safety 

• By quantities contained per outer package—DOT restricts on passenger 

aircraft the quantity of certain substances or the number of articles that 

may be present in the outermost shipping containers in the cargo hold. For 

example, DOT allows the carriage of up to 30 liters of certain highly 

flammable liquids per outer package on cargo aircraft, but imposes limits 

of 1 liter or less on passenger aircraft. 

• By packaging integrity—dangerous goods must be packaged so as to 

protect the integrity of the shipment and safeguard against accidental 

leaks or spills. 

For passenger aircraft, whose cargo areas are divided into multiple 

compartments, DOT also restricts the aggregate quantities of dangerous 

goods that may be carried per cargo compartment. Figure 2 shows the 

kinds of containers in which dangerous goods typically travel in these 

cargo compartments. 

Figure 2: Dangerous Goods Cargo Containers 
Page 8 GAO-03-22 Aviation Safety 

Dangerous goods permitted onboard passenger aircraft include dry ice and 

solvents; cargo aircraft may also carry materials such as paint or medical 

waste. Table 1 provides a complete listing of the nine classes of dangerous 

goods, their descriptions, an example for each class, and some of the 

restrictions DOT places on the carriage of each by type of aircraft. 

Table 1: Dangerous Goods Classes and Descriptions 

Class Description Example(s) Cargo aircraft restrictions 

Passenger aircraft 

restrictions 

1 Explosives Fireworks Most are forbidden Most are forbidden 

2 Gases Propane Most are permitted within 

quantity limitations 

Most are forbidden 

3 Flammable liquids Acetone, lighter fluid, paints Most are permitted, except 

those that are toxic by 

inhalation 

Most are permitted within 

quantity limitations 

4 Flammable solids Safety matches Most are permitted within 

quantity limitations; others are 

forbidden (for example, 

spontaneously combustible 

materials) 

Most are permitted within 

quantity limitations 

5 Oxidizers and organic 

peroxides 

Swimming pool chemicals Most are permitted within 

quantity limitations; others are 

forbidden (for example, 

temperature-controlled organic 

peroxides) 

Most are permitted within 

quantity limitations 

6 Toxic materials and 

infectious substances 

Regulated medical waste, 

motor fuel anti-knock mixtures

Most are permitted within 

quantity limitations, exceptions 

for subsidiary risksa

 or those 

that are toxic by inhalation 

Most are permitted within 

quantity limitations 

7 Radioactive materials Uranium hexafloride b b 

8 Corrosive materials Batteries, cleaning 

compounds 

Most are permitted within 

quantity limitations 

Most are permitted within 

quantity limitations 

9 Miscellaneous dangerous 

goods 

Asbestos Most are permitted within 

quantity limitations 

Most are permitted within 

quantity limitations 

Source: U.S. Department of Transportation, RSPA. 

a

“Subsidiary risk” means that the dangerous good also meets the definition of one or more other 

classes. 

b

For nearly all radioactive materials, the Department of Transportation’s Research and Special 

Programs Administration (RSPA) spells out restrictions in terms of the radiological reading that comes 

from the package rather than a quantity limit (as it does for other classes of dangerous goods). 

According to the U.S. Census Bureau’s most recent survey on the 

movement of hazardous goods in the United States, class 3 dangerous 

goods (flammable liquids, such as paint) account for the greatest portion 

(by weight) of the nine classes of dangerous goods shipped by air. 

However, the vast majority of flammable liquids travel by other modes. 

The percentage of total shipments made by air was greatest for radioactive 
Page 9 GAO-03-22 Aviation Safety 

materials (class 7)—just over 8 percent of the total radioactive tonnage 

shipped in 1997 was shipped by air. According to FAA, cargo aircraft, such 

as those operated by the major delivery services FedEx and United Parcel 

Service, Inc. (UPS), carry about 75 percent of the nation’s dangerous 

goods air shipments. The remaining 25 percent travel onboard passenger 

aircraft in cargo compartments. 

Ensuring the safe transportation of dangerous goods by air is a shared 

responsibility of federal agencies, shippers, and airlines—the success of 

which ultimately depends on the efforts of thousands of individuals every 

day. Within DOT, the following have responsibility for dangerous goods: 

• The Research and Special Programs Administration (RSPA) regulates the 

transportation of dangerous goods by truck, train, ship, pipeline, and 

plane. It decides which materials to define as hazardous; writes the rules 

for packaging, handling, and carrying them; and prescribes training 

requirements for shippers’ and carriers’ dangerous goods employees. 

RSPA, along with the other DOT operating administrations that operate 

and manage dangerous goods programs,4

 conducts inspections and 

investigations to determine compliance with dangerous goods laws and 

regulations for all modes of transportation and, where appropriate, 

initiates enforcement actions against those it finds not to be in 

compliance. RSPA maintains a database for closed dangerous goods 

enforcement actions from these operating administrations, and another 

database that tracks dangerous goods incidents from these operating 

administrations. 

• The Office of Intermodalism, reporting to the Secretary of Transportation, 

is responsible for implementing recommendations from a March 2000 

evaluation of DOT’s dangerous goods program,5

 coordinating intermodal 

and cross-modal dangerous goods activities, and coordinating DOT-wide 

outreach activities. For example, in 2001, to improve awareness of 

dangerous goods incidents occurring during shipments, this office sent out 

letters to shippers most frequently identified in RSPA’s dangerous goods 

incident database. 

 4

The DOT operating administrations that operate and manage dangerous goods programs 

include the Federal Aviation Administration, the Federal Motor Carrier Safety 

Administration, the Federal Railroad Administration, the Research and Special Programs 

Administration, and the United States Coast Guard. 

5

U.S. Department of Transportation, Departmentwide Program Evaluation of the 

Hazardous Materials Transportation Program, Final Report (March 2000). 
Page 10 GAO-03-22 Aviation Safety 

• FAA carries out responsibilities for ensuring compliance with the rules for 

transporting dangerous goods by air. In addition, FAA assesses carriers’ 

operations and investigates dangerous goods incidents or accidents. FAA 

also has other responsibilities, including those relating to the prosecution 

and adjudication of enforcement actions against those found to have 

violated the dangerous goods rules. 

The Postal Service is both a carrier and a shipper of dangerous goods 

because it not only carries shipments on aircraft that it leases, but it also 

sends U.S. mail onboard commercial passenger and cargo airlines. As a 

result, the airlines carrying U.S. mail rely on the Postal Service as a first 

line of defense in ensuring the safety of the packages they accept for 

transport and in preventing the shipment of anything that should not travel 

by air. 

Shippers—whether they are businesses or individuals—have the primary 

responsibility for ensuring the safety of their dangerous goods shipments. 

They are required to train their employees to package their shipments 

safely and to tell the carriers to whom they deliver these shipments that 

they contain dangerous goods. Carriers share some of the responsibility 

for the safe transportation of dangerous goods. They do so by training 

their employees to handle these shipments properly, to identify likely 

instances of improper shipments (such as those containing undeclared 

dangerous goods), and to verify that the indirect air carriers from whom 

they accept consolidated cargo shipments have FAA-approved security 

programs in place to prevent explosive or incendiary devices from being 

placed onboard.6

 Carriers are also responsible for reporting to DOT any 

instance of noncompliance they discover. 

 6

An indirect air carrier accepts and delivers cargo to commercial airlines for transport. An 

example of an indirect air carrier would be a freight forwarder that consolidates shipments 

from a large number of shippers and then transports them via the cargo compartments of 

commercial aircraft. Because the U.S. Postal Service uses commercial aircraft to ship the 

mail, the FAA also considers it an indirect air carrier. 
Page 11 GAO-03-22 Aviation Safety 

From tragic accidents over the years and day-to-day experience in 

handling cargo traffic, DOT and major carriers know that shipments of 

undeclared dangerous goods can have disastrous consequences. The 

nature and frequency of such shipments—and, by extension, the amount 

of effort that should be put into stopping them—are difficult to estimate 

because of data limitations. However, the inability of commercially 

available screening equipment to detect many types of dangerous goods, 

the costs of delaying shipments to inspect them, and restrictions against 

opening certain packages may preclude the collection of data. 

Undeclared and other improper shipments of dangerous goods can pose a 

high risk because of the nature of air transportation. In recent years, both 

RSPA and FAA have expressed concern about undeclared dangerous 

goods shipments. In its departmentwide March 2000 evaluation of the 

dangerous goods program, DOT reported that the United States has a 

relatively good safety record, given the amounts of dangerous goods that 

are shipped by all modes of transportation each year. However, DOT 

added that the potential still remains for dangerous goods incidents with 

catastrophic consequences, and, even though relatively small amounts of 

dangerous goods travel by air (compared with other modes of 

transportation), a single mishap can have serious consequences. For 

example, FAA has reported the following incidents: 

• In 1996, a major passenger airline carried undeclared dangerous goods—

calcium hypochlorite and liquid bleach—on a flight from California to 

Jamaica. Upon arrival, airport personnel discovered smoke coming from 

the aircraft’s cargo doors and encountered toxic fumes when they opened 

the cargo compartment. The box of undeclared dangerous goods was 

leaking and burst into flames shortly after the airport personnel removed it 

from the cargo hold. 

• In 1998, an undeclared shipment of electric storage batteries (considered 

“wet” because they contain either electrolyte acid or alkaline corrosive 

battery fluid) burst into flames while en route by truck to an airport, 

where it had been scheduled to be placed aboard a major passenger 

carrier’s aircraft. 

• In 1999, a major cargo carrier transported an undeclared shipment of 

liquefied petroleum gas from Portland, Oregon, to New York on a regularly 

Shipments of 

Undeclared 

Dangerous Goods Can 

Have Serious 

Consequences, but 

Their Nature and 

Frequency Are 

Difficult to Estimate 

Consequences of Carrying 

Undeclared Dangerous 

Goods Have Been Serious 

and Remain a Concern 
Page 12 GAO-03-22 Aviation Safety 

scheduled cargo flight. One day after arriving in New York, the package 

burst into flames at the carrier’s sorting facility. 

Three of the four major carriers we interviewed and DOT expressed 

concern about the safety of carrying dangerous goods. According to these 

three carriers, even though they discover relatively few undeclared 

shipments, their greatest safety concern in the air transportation of these 

goods is prompted by the undeclared shipments—particularly those they 

do not detect before accepting them. They expressed this concern over 

not knowing how much of the volume of undeclared dangerous goods they 

do not find, because these shipments present a greater risk than do those 

that shippers properly declare. 

The major cargo carriers we interviewed and the Postal Service agreed 

that ignorance or misunderstanding of the rules for transporting 

dangerous goods is by far the most common reason why shippers fail to 

properly declare their dangerous goods shipments. According to one 

carrier, in very limited instances, shippers will deliberately not declare 

their shipments even when they know they are breaking the rules. 

However, no carrier cited cost as a reason why shippers fail to declare 

their shipments, even though shipping costs are usually higher for 

dangerous goods than for nondangerous goods. An official from one 

carrier stated that he had never seen a case of a shipper willfully failing to 

properly declare a dangerous goods shipment because of cost concerns. 

Furthermore, at the Postal Service, it is doubtful that cost is a cause of 

undeclared shipments, because the Postal Service does not charge more 

for carrying these shipments than it does for carrying those that are not 

hazardous; all of the Postal Service’s charges are based on weight and 

class, regardless of the contents. 

According to a 1999 threat assessment published by DOT’s Volpe Center,7

three types of data that are needed to thoroughly assess the risks of 

carrying declared and undeclared dangerous goods by air were 

unavailable. These were 

 7

The John A. Volpe National Transportation Systems Center is part of RSPA. It provides 

policy support, strategic planning, and analysis to customers within as well as outside DOT 

in areas such as strategic investment and resource allocation. Its work addresses issues in 

air and other modes of transportation. 

Data Limitations Make 

Estimates of Undeclared 

Dangerous Goods 

Shipments Difficult 
Page 13 GAO-03-22 Aviation Safety 

• what amounts of dangerous goods are shipped by class and division (for 

all modes of transportation), 

• how often incidents related to dangerous goods involve undeclared 

shipments, and 

• what amounts and what types of undeclared dangerous goods are shipped 

by air. 

Without these data, the Volpe Center was limited to assessing the threat 

from dangerous goods instead of the risk. The danger associated with a 

specific item is its “threat,” while the likelihood that the threat will actually 

result in harm is its “risk.” Assessing risk, according to the Volpe Center, 

requires some indication of the likelihood that dangerous goods will be 

present on an aircraft—and the data to determine this likelihood were not 

available. 

Volpe Center officials attempted to find or compile data sources that 

would allow them to estimate the total amount of various dangerous goods 

that might be shipped (for example, over the course of a year), but they 

were unsuccessful. They found no single source of such data and were not 

able to piece together data sources. For example, Volpe Center staff 

attempted to compile data from chemical manufacturers to identify the 

total amounts of their products that move by air and the related 

distribution chain (that is, the amounts that move by other modes); this 

information would enable them to identify aggregate amounts of certain 

dangerous goods that shippers should be declaring, which would be a first 

step in working toward an estimate of undeclared shipments. However, 

the industry sources the Volpe Center consulted considered such 

information proprietary and would not share it. Volpe Center staff also 

considered assembling cargo manifest information from the airlines, 

because these records indicate for each flight the amounts and types of 

dangerous goods the aircraft is carrying. However, Volpe Center staff said 

the airlines informed them that these data are not in a form usable for such 

an analysis. Even if the manifest information were available, data on the 

overall amounts of dangerous goods shipments (such as the Volpe Center 

sought from the chemical industry) would still be necessary before this 

manifest information could be useful for estimating undeclared dangerous 

goods shipments. 

According to Volpe Center staff, the limitations in the amount and quality 

of data on dangerous goods shipments make estimating how many 

shipments contain undeclared dangerous goods more difficult. Our 
Page 14 GAO-03-22 Aviation Safety 

experts in applied research and methodology agreed, noting that certain 

“hidden populations” methods might be useful for estimating the amount 

of undeclared dangerous goods shipments,8

 but only if data limitations 

such as those the Volpe Center identified were overcome. A Massachusetts 

Institute of Technology expert in transportation research with whom we 

met agreed that none of the known methods for estimating hidden 

populations would be feasible for undeclared dangerous goods. 

The major carriers we interviewed said they most commonly identify 

undeclared dangerous goods (after accepting them for shipment) when 

some occurrence prompts them to open a package or, in the case of the 

Postal Service, to set the package aside for further investigation (because 

the Postal Service generally cannot open such a package without a search 

warrant). Most often, this happens when a package leaks, spills, breaks 

open, or emits an odor, and the carrier or Postal Service employees 

identify the occurrence as potentially a dangerous goods incident.9

 One 

carrier also indicated that occasionally packages open as a result of 

handling or must be opened when they lose their address labels. In some 

of these instances, the company has discovered undeclared dangerous 

goods. This same company also noted that, on rare occasions, it learns of 

undeclared dangerous goods from informants—employees of either the 

company that shipped the package or competitors of that company. 

The carriers we interviewed reported that, although they have the consent 

of shippers to open packages that have been accepted for shipment, they 

seldom discover undeclared dangerous goods. Although they did not cite a 

specific percentage, they described shipments of undeclared dangerous 

goods as “very rare” and “a handful.” The numbers are believed to be 

similarly small for the Postal Service—officials estimated that declared 

dangerous goods represent less than one-tenth of 1 percent of their 

shipments, and the percentage of these shipments that is undeclared is 

 8

The term “hidden populations” refers to those that are difficult to count by traditional 

means because, for example, they involve illegal or undesirable conditions that people are 

unlikely to self-report. For example, illegal aliens or intravenous drug users would be 

considered “hidden populations,” as would persons deliberately shipping undeclared 

dangerous goods. 

9

A dangerous goods incident is an event that results in a release, including an unanticipated 

or unintentional release, of hazardous material during the course of transportation. RSPA 

requires carriers to report incidents as soon as possible when they involve certain serious 

consequences, such as deaths or a change in the operational flight pattern of an aircraft. 

RSPA requires carriers to report all other incidents to the agency within 30 days of their 

occurrence. 
Page 15 GAO-03-22 Aviation Safety 

“very small.” The Volpe Center reported in a 1999 threat assessment that 

undeclared dangerous goods shipments made up about 0.05 percent of the 

shipments of several large cargo carriers, but this estimate was based on 

the recollections of the carriers of how many incidents they typically 

report to RSPA. 

Because estimates by the Volpe Center, major carriers, and the Postal 

Service are based on reported incidents or memory, they are incomplete. 

Moreover, these estimates refer only to those undeclared shipments that 

resulted in dangerous goods incidents—they do not include undeclared 

shipments that never gave carriers cause to open them. As a result, 

according to the Volpe Center, there are no valid figures for the numbers 

of dangerous goods shipments that do not comply with regulations for 

transportation by air.10

Additionally, when a carrier reports an incident to DOT, RSPA does not 

currently require the carrier to report whether the shipper properly 

declared the dangerous goods. Consequently, the estimates of undeclared 

shipments reported by the Volpe Center and by carriers to us may not 

include all of the incidents carriers discovered, because the estimates are 

based on memory and are therefore subject to error. RSPA plans to 

remedy this limitation by requiring carriers to report whether dangerous 

goods shipments involved in incidents were declared or undeclared. To do 

so, RSPA is modifying its incident-reporting paperwork (Form 5800.1) to 

more systematically collect and analyze information on undeclared 

shipments. RSPA expects to complete this and other ongoing revisions to 

its incident-reporting form by spring 2003. 

 10Recently, RSPA received comments on the frequency of undeclared shipments in 

response to an advanced notice of proposed rulemaking. RSPA received these comments 

under Docket HM-228, which considers changes to the regulations on the transportation of 

hazardous materials. According to an RSPA official, the agency is analyzing these 

comments and expects to complete its analysis by the end of October 2003. 
Page 16 GAO-03-22 Aviation Safety 

Technological limitations complicate efforts to estimate the incidence of 

undeclared dangerous goods shipments. Ideally, technologies generally 

considered to be less intrusive, such as X-ray or explosives-detection 

equipment, could be used to identify and characterize undeclared 

shipments. The Transportation Security Administration (TSA)11 is 

currently using this equipment to screen passenger carry-on and checked 

baggage for weapons and explosives, and, under the Aviation and 

Transportation Security Act,12 TSA must ensure that a system is in 

operation to screen, inspect, or otherwise provide for the security of all air 

cargo to be transported in all cargo aircraft as soon as practicable. 

However, X-ray and explosives-detection equipment is not designed to 

detect many types of dangerous goods.13 In the future, technology may 

enable the rapid, less intrusive screening of packages, but in the near term, 

opening packages remains the best way to obtain information on the 

nature and frequency of undeclared shipments. 

Economic obstacles—particularly the costs of opening packages after 

accepting them—also make it difficult to estimate the nature and 

frequency of undeclared dangerous goods shipments. According to each of 

the major carriers we interviewed, the volume of cargo that these airlines 

carry each day is tremendous. For example, the carriers stated that they 

carry from at least 1.3 million to more than 2 million shipments each night, 

a small fraction of which contain dangerous goods. Because the carriers 

typically guarantee delivery on nearly all of the shipments they carry (such 

as within 24 hours or 2 business days), anything that slows their ability to 

move shipments could compromise their ability to meet their guarantees 

to their customers and, as a result, hurt their competitive position in their 

industry. 

Although the carriers we interviewed told us that they obtain the consent 

of shippers to open packages, they also said they seldom do open 

packages. Carriers and an association representing cargo and passenger 

airlines stressed that they are not in the business of opening packages, 

particularly when shippers are primarily responsible for ensuring the 

 11The Homeland Security Act of 2002, P.L. 107-296, provides that TSA be transferred to the 

Department of Homeland Security. The Under Secretary for Border Transportation and 

Security has responsibility for TSA. 

12P.L. 107-71, November 19, 2001. 

13We do not describe how this technology works because TSA considers this to be sensitive 

security information. 

Technological, Economic, 

and Legal Hurdles Also 

Make Estimates of 

Undeclared Dangerous 

Goods Shipments Difficult 
Page 17 GAO-03-22 Aviation Safety 

integrity and proper declaration of those packages. The carriers indicated 

that they have confidence in and place a great, ongoing emphasis on their 

up-front screening to prevent shippers from offering them undeclared 

dangerous goods in the first place. Opening packages without probable 

cause to do so would also be costly to the carriers because they would be 

responsible for repackaging anything they found to be properly declared—

and dangerous goods require special, more expensive packaging than 

other shipments. Although carriers remain concerned about the possibility 

of undeclared shipments they may miss, to date the frequency with which 

they discover shipments of undeclared dangerous goods does not, in their 

view, justify a step as disruptive and costly as systematically opening a 

random or targeted selection of shipments. 

Because the Fourth Amendment to the Constitution prohibits 

unreasonable searches and seizures and neither DOT nor the Postal 

Service has obtained the consent of owners to have their packages opened 

for inspection, neither agency may conduct or require random or targeted 

intrusive inspections of domestic cargo shipments to look for undeclared 

dangerous goods. Although FAA may remove a package from an aircraft 

and take such emergency actions if it reasonably believes that the package 

presents an immediate threat, it has no authority, generally, to open and 

inspect a package without a warrant or without the owner’s consent. 

The Postal Service may inspect Parcel Post packages. However, packages 

sent as First Class or Express mail traveling by air may not be inspected.14

The mail classification schedule recommended by the Postal Rate 

Commission and adopted by the Postal Service does not distinguish 

between letters and packages, treating both as “sealed against inspection” 

and protected by the Fourth Amendment. Thus, these packages are 

protected to the same extent as letters, and all First Class and Express 

mail is treated as protected by the Fourth Amendment. 

 14The Postal Reorganization Act, 39 U.S.C. § 3623(d), addresses the issue of letters sealed 

against inspection. It states, “The Postal Service shall maintain one or more classes of mail 

for the transmission of letters sealed against inspection... No letter of such a class of 

domestic origin shall be opened except under authority of a search warrant authorized by 

law, or by an officer or employee of the Postal Service for the sole purpose of determining 

an address at which the letter can be delivered, or pursuant to the authorization of the 

addressee.” 
Page 18 GAO-03-22 Aviation Safety 

To obtain more information on the nature and frequency of undeclared 

dangerous goods in air transport, FAA has teamed with the U.S. Customs 

Service, which has the authority to inspect and search international cargo 

(imports and exports). Specifically, the Customs Service can and does 

randomly open and inspect international cargo for purposes such as 

ensuring that shippers have paid the proper tariffs. Most recently, in June 

and July 2000, the U.S. Customs Service and FAA together conducted 

inspections of passenger carry-on and checked bags and cargo aboard 

flights that were entering or departing from the United States at 19 

domestic airports.15 This series of inspections found that 

• 8 percent of targeted cargo shipments (those whose tariff codes indicated 

that their contents might be hazardous) contained undeclared dangerous 

goods, 

• 1 percent of passenger carry-on bags contained undeclared dangerous 

goods, and 

• just under 0.5 percent of passenger checked baggage contained 

undeclared dangerous goods. 

The undeclared dangerous goods in the cargo shipments included 

flammable liquids, fuel control units, aerosols, fire extinguishers, and 

devices powered by flammable liquid. In the passengers’ checked and 

carry-on bags, the Customs-FAA teams found aerosols, lighters, flammable 

liquids, safety matches, compressed flammable gases, and automotive 

batteries. The Customs-FAA team randomly selected the passenger 

baggage it inspected, but for the cargo, the team matched tariff codes for 

commodity imports and exports with a dangerous goods trigger list to 

determine which shipments to inspect.16

 15Final Report of Operation Clear Sky, Joint Inspection Activity, United States Customs 

Service/Federal Aviation Administration, June 26–July 21, 2000. 

16The Customs-FAA inspections focused on international cargo and passenger baggage 

because the Customs Service has the authority to open and inspect shipments coming into 

or leaving the United States. Beyond the border, neither agency has the authority to open 

and inspect domestic cargo or passenger baggage without a search warrant. 

DOT Has Teamed with the 

U.S. Customs Service to 

Obtain Information on 

Undeclared Dangerous 

Goods in International 

Shipments 
Page 19 GAO-03-22 Aviation Safety 

DOT has tried several times to clarify and expand its authority to inspect 

and open certain packages when its inspectors suspect a violation of the 

dangerous goods regulations. In its 1997, 1999, and 2001 reauthorization 

proposal, DOT sought the authority to access, open, examine, and, if need 

be, remove a package from transportation if it had an objectively 

reasonable and articulable belief that the package might contain 

undeclared dangerous goods.17 According to DOT, this authority, which is 

specific to all modes, would require its officers or inspectors to have a 

“particularized and objective basis” for suspecting a violation, such as a 

pattern of shipping undeclared dangerous goods, in order to open an 

unmarked package. DOT further stated that this enhanced authority would 

enable it to more effectively detect potential violations and to ensure that 

it took the appropriate remedial actions. According to DOT officials, its 

reauthorization proposal has not been enacted for reasons unrelated to the 

merits of its request for additional inspection authority. 

Because DOT’s reauthorization proposal applies equally to all modes of 

transportation, it would, if approved, allow DOT to follow up on problem 

shippers across the modes. However, the proposal would also extend the 

government’s inspection authority without regard to the differences 

inherent in transporting dangerous goods by different modes. The same 

distinctions between air and the other modes that justify more stringent 

regulations for transporting dangerous goods by air might also justify 

greater inspection authority for packages shipped by air. 

A primary objective of DOT’s reauthorization proposal has been to 

improve the ability of its inspectors to monitor and enforce the dangerous 

goods regulations. The proposal has not been designed to obtain better 

information about the nature and frequency of undeclared air shipments. 

Because it would require a “particularized and objective basis” for opening 

packages, it would not allow DOT to identify a random sample of packages 

and conduct inspections whose results could be generalized to all 

packages in air transport. Thus, its usefulness as a tool for gathering data 

to estimate the nature and frequency of undeclared air shipments and to 

profile and target violators would be limited. DOT officials agree that their 

proposal would not generate statistically valid data, and they have 

indicated their willingness to modify the proposal so that it would yield 

more useful information. 

 17In this report, we are not expressing an opinion on potential constitutional issues related 

to DOT’s proposal. 

Increased Inspection 

Authority That DOT Is 

Seeking Would Not 

Produce Statistically Valid 

Data and Does Not 

Distinguish between Air 

and Other Modes of 

Transportation 
Page 20 GAO-03-22 Aviation Safety 

An alternative to DOT’s proposal, based on the premise that additional and 

perhaps unique measures are needed to protect air commerce, would 

require that shippers consent to DOT’s opening packages shipped by air 

for inspection. This would allow the department to select and open a 

random sample of packages in order to gather statistically valid data on 

undeclared air shipments. 

To prevent dangerous goods shipments from compromising aviation 

safety, the federal government relies on regulation, research, and 

outreach, while private industry depends on policies for dealing with 

known shippers, other restrictions, training, and sanctions. 

Federal regulations provide a framework for transporting dangerous 

goods safely by air. As discussed in the background section of this report, 

these regulations define dangerous goods, identify those that may and may 

not travel by air, and specify how the materials are to be packaged, 

handled, and carried. In addition, the regulations prescribe initial and 

recurrent training for shippers’ and carriers’ employees, and require 

shippers and carriers to test their employees’ understanding of the 

material covered in the training. The training, which is designed to 

increase dangerous goods employees’ safety awareness and to reduce the 

frequency of dangerous goods incidents, is important because insufficient 

understanding of the rules is often a factor contributing to such incidents. 

For example, in 17 of 25 dangerous goods enforcement cases we reviewed 

involving businesses, FAA identified employees’ lack of training as a 

contributing factor.18

To monitor the effectiveness of its regulations in promoting safety, RSPA 

collects information on dangerous goods incidents occurring in the air, 

 18The remaining 5 cases of the 30 we reviewed involved individuals not engaged as 

HAZMAT employees, to whom the rules regarding initial and recurrent training do not 

apply. 

Government and 

Industry Rely on 

Several Mechanisms 

to Prevent Dangerous 

Goods Shipments 

from Compromising 

Safety 

The Federal Government 

Depends on Regulations, 

Research, and Outreach to 

Prevent Problems 
Page 21 GAO-03-22 Aviation Safety 

water, rail, and truck modes through its Form 5800.1. Nonetheless, the 

form is not designed to collect all the information that would be useful in 

monitoring the effectiveness of DOT’s dangerous goods regulations. As 

previously noted, the form does not ask whether a problem shipment was 

declared or undeclared—a key question in assessing effectiveness. 19 In 

addition, the form does not include data fields that precisely identify the 

different types of packaging deficiencies. While the form has space for 

written comments, there is no mechanism for standardizing and entering 

the information from the comments into DOT’s databases. RSPA is 

revising the form to overcome these limitations. Once carriers begin 

collecting information on dangerous goods incidents using this revised 

form, better information on the incidence of undeclared shipments and 

reasons for packaging deficiencies should be available to FAA and the 

other operating administrations. 

In the course of such monitoring, DOT sometimes identifies safety issues 

that require further research. For example, DOT is currently evaluating 

ways in which it will strengthen the regulations for shipping batteries, 

because its analysis indicated that the existing dangerous goods 

regulations for these shipments may not be sufficient. Beginning in the 

early 1990s, FAA identified a number of incidents associated with 

batteries, particularly lithium batteries, aboard aircraft in which the 

batteries caused fires, smoke, or extreme heat—precisely the kind of 

effects that make dangerous goods dangerous. In response to these and 

other concerns, RSPA has taken a number of actions designed to improve 

the regulations for the transportation of lithium batteries.20

FAA’s monitoring of reports on incidents involving dangerous goods also 

led to further work on packaging standards. In examining nearly 3,000 

reports from 1998 and 1999, FAA found that 60 percent of the incidents 

involved properly declared shipments, indicating that the shipments 

 19Two DOT initiatives—the Flagship Initiative on Hazardous Materials Handling/Incidents 

and the DOT-wide program evaluation—cited a better understanding of the frequency and 

impact of undeclared shipments as essential. 

20In response to an incident at Los Angeles International Airport in 1999, the National 

Transportation Safety Board issued five safety recommendations to RSPA for improving 

the transportation of lithium batteries. In response to these concerns, RSPA published 

safety advisories in the Federal Register, worked with the lithium battery industry to adopt 

voluntary safety standards, undertook a study on the transportation of lithium batteries, 

and initiated changes to domestic and international regulations on the transport of lithium 

batteries. 
Page 22 GAO-03-22 Aviation Safety 

complied with the existing packaging standards. Yet just over half (873) of 

these properly declared shipments had problems because their packaging 

failed—that is, their closures or seals leaked. These data prompted FAA to 

attempt to determine the adequacy of packaging standards for air 

transportation and the likely causes of leaking closures and seals. 

Observing an increase in the number of package failures in the past 3 

years, FAA questioned whether the existing test methods simulate the 

realistic combined effects of pressure, temperature, and vibration. As a 

result, FAA contracted with Michigan State University to study packaging 

in air transportation. The results of that study, which FAA recently 

received, indicate that closures are continuing to leak in packages marked 

as complying with existing packaging standards. Subjecting packages to 

both high altitude and vibration resulted in a package failure rate of 50 

percent. RSPA is reviewing these results. 

To help prevent dangerous goods incidents aboard passenger aircraft, FAA 

and RSPA conduct outreach to the public. For example, FAA worked with 

RSPA to develop for air travelers a brochure that lists items prohibited in 

passenger baggage (see app. I). The brochure also explains that in-flight 

variations in temperature and pressure can cause seemingly harmless 

items to leak or generate toxic fumes during air travel. RSPA requires that 

signs be posted in airport terminals and at check-in counters listing items 

prohibited in air travel, some of which passengers may not recognize as 

hazardous in air transportation. In addition, FAA has placed kiosks with 

information on dangerous goods at 24 major airports to better inform the 

general public about items that are considered hazardous onboard aircraft. 

The Postal Service also does consumer outreach to better inform the 

public about the materials that may and may not be sent through the mail. 

According to Postal Service officials, there are posters in all of its facilities 

that warn customers about shipping restricted dangerous goods. In 

addition, for any customer who ships or requests information about 

shipping dangerous goods, Postal Service retail employees provide an 

informational brochure summarizing the applicable rules as well as the 

shipper’s responsibilities. 
Page 23 GAO-03-22 Aviation Safety 

To prevent undeclared dangerous goods shipments, major carriers limit 

their business to known shippers and may impose other restrictions. They 

also train their employees to be a first line of defense against undeclared 

shipments, and may apply sanctions to shippers who have violated 

dangerous goods regulations. 

To ensure that they are dealing with legitimate businesses that are more 

likely to properly train their employees to comply with dangerous goods 

rules, the major carriers we interviewed rely on TSA’s “known shipper” 

requirements or establish formal, contractual relationships with their 

shippers that mirror the known shipper requirements.21 According to 

officials of one of the carriers, the steps involved in becoming a known 

shipper reduce to an acceptable level the risk that the shipper presents to 

the carrier.22 By contrast, the carriers have found, casual or one-time 

shippers are more likely to offer undeclared dangerous goods for 

shipment. Three of the four carriers said they try to limit their business 

with casual or one-time shippers and do not advertise to them. Rather, two 

of the carriers said, they target business-to-business shippers that typically 

have experience with shipping high volumes of dangerous goods and may 

have long-standing relationships with the carriers. The fourth carrier said 

that it does not accept dangerous goods from casual shippers at all and, 

for other shippers, requires the establishment of a dangerous goods–

shipping agreement, or contract, that spells out obligations for shippers, 

such as recurring employee-training requirements. Officials of this carrier 

believe that these contractual obligations reduce the incidence of 

undeclared shipments. 

 21We have not included a detailed description of the criteria that shippers must meet for 

carriers to consider them “known” because TSA considers this to be sensitive-security 

information. 

22Recent media reports as well as work by the DOT Inspector General have raised concerns 

about the extent to which (1) the known shipper procedures are a reliable deterrent to 

criminal attacks and (2) selected carriers were adequately complying with regulations 

requiring them to, among other things, properly screen packages from unknown shippers. 

Most recently, virtually all of the cargo carriers the Inspector General tested were 

complying with the requirement, put in place after September 11, 2001, to take no packages 

from unknown shippers. However, the Inspector General raised additional serious 

concerns about weaknesses in FAA’s procedures for individuals or businesses to become 

approved indirect air carriers. (A carrier using the known shipper requirements must verify 

that shippers have such approval from FAA.) 

Major Carriers Rely on 

Known Shipper Policies, 

Other Restrictions, 

Training, and Sanctions to 

Prevent Undeclared 

Shipments 

Carriers Deal with Known 

Shippers and Impose Other 

Restrictions 
Page 24 GAO-03-22 Aviation Safety 

Besides limiting their business primarily to known shippers, the major 

carriers we interviewed may try to prevent undeclared shipments by 

limiting the types of materials they will carry and the places where they 

will accept dangerous goods shipments. Three of the four carriers said 

they accept fewer types of dangerous goods for shipment than DOT 

authorizes to travel by air. For example, the carriers said they refuse to 

carry materials such as toxic or infectious substances, certain explosives, 

and organic peroxides. In addition, one of the carriers said it would not 

accept dangerous goods shipments at its retail establishments. This carrier 

said it would accept such shipments only when its own drivers picked 

them up from established customers. This carrier’s policy is designed to 

screen out the casual shippers that might use its retail establishments. 

According to the carrier, this policy also allows it to rely on its drivers’ 

experience with dangerous goods shipments, their training, and their longstanding relationships with established customers as a first line of 

screening against undeclared shipments of dangerous goods. 

While the Postal Service cannot limit its business to known shippers, it 

accepts fewer dangerous goods for shipment than DOT authorizes to 

travel by air. In general, the Postal Service limits the dangerous goods it 

will accept for shipment to certain quantities of consumer commodities 

that typically present a limited hazard in transportation because of their 

form, quantity, or packaging. 

In addition to limiting what dangerous goods it will carry, the Postal 

Service, as part of its aviation mail security program, requires customers 

to bring any package weighing 16 ounces or more to a post office for 

shipment. The intent of this program is to prevent explosives in the mail, 

but Postal Service officials indicated it has a residual benefit in helping to 

prevent undeclared shipments of dangerous goods. Specifically, by 

requiring customers to bring packages that weigh 16 ounces or more to a 

post office for shipment, Postal Service employees can inspect packages, 

ask questions about their contents to determine whether they contain 

anything prohibited, and ensure proper handling for packages containing 

dangerous goods that may be mailed. 

The major carriers we interviewed emphasized that the training they 

provide for their employees is a key component in their efforts to prevent 

shippers from offering undeclared dangerous goods, supplementing their 

use of restrictions or the known shipper requirements to guard against 

such shipments. This training provides information on dangerous goods 

requirements and procedures for drivers and employees who handle, sort, 

and load shipments. Through this training, the carriers expect that 

Carriers Train Their Employees 

to Monitor Compliance with 

Dangerous Goods 

Requirements 
Page 25 GAO-03-22 Aviation Safety 

employees throughout their distribution chain will be able to identify 

problems such as declaration paperwork that is missing information about 

the contents of a package labeled as dangerous. 

Carriers rely particularly on their drivers to draw on their training to, in 

effect, extend the known shipper concept to their day-to-day interactions 

with shippers. Training, plus a working knowledge of a company’s 

established customers, helps the drivers detect inadvertent failures to 

properly declare a shipment. For example, a driver picking up a shipment 

from a customer who typically sends some dangerous goods would be 

expected to raise questions if the customer did not label or declare any of 

the packages as dangerous. In such an instance, the shipper may have 

made a mistake or forgotten to declare the dangerous goods. 

The Postal Service trains its retail employees, who accept packages from 

the public, to screen packages and prevent those with undeclared or 

improperly packaged dangerous goods from entering the mail system. 

According to Postal Service officials, as of August 2002, the agency had 

trained all 131,000 of its retail employees in procedures for preventing the 

acceptance of any package containing prohibited materials. These 

procedures include (1) asking shippers a series of questions about the 

contents of their packages, including whether the packages contain 

anything hazardous; (2) visually inspecting packages to look for signs of 

problems, such as leaks, the lack of a return address, or markings 

indicating that a package contains something a shipper may not know is 

hazardous; and (3) referring to a reference guide for assistance in 

answering shippers’ questions about items that may or may not be 

permissible in the U.S. mail. (See app. II for a summary of DOT’s 

dangerous goods classes and the materials or quantities from each that are 

allowed in the U.S. mail.) While the retail employees may be the first to 

deal with shipments entering the mail system, the Postal Service also 

provides dangerous goods training to its non-retail employees (such as 

postal inspectors or employees at business mail entry units), who also 

handle or carry dangerous goods or respond to incidents involving them. 

According to the official responsible for the Postal Service’s dangerous 

goods program, the agency has to rely on its retail employees to screen out 

unacceptable items because it has limited authority to open mail that has 

been accepted for shipment. These officials believe that face-to-face 

questioning reduces the anonymity associated with depositing a letter in a 

mailbox. And reducing anonymity, this official says, improves their 

confidence in shippers’ statements about the contents of packages. To test 

its retail employees’ performance in specific aspects of customer service, 
Page 26 GAO-03-22 Aviation Safety 

the Postal Service has an ongoing “mystery shopper” program in which its 

employees pose as customers. In late 2001, the Postal Service began 

including in the mystery shopper tests a determination of whether the 

retail employees were following requirements for asking the question 

about dangerous goods. To date, the Postal Service’s tests indicate that the 

retail employees asked the required screening question 69 percent of the 

time. When the retail employees failed to ask the dangerous goods 

question, Postal Service officials said they provided feedback and 

retrained the employees. These officials also told us that they provided 

this feedback to each postal office manager and have incorporated targets 

for improved performance on the mystery shopper tests into the managers’ 

performance goals. Officials say these results are slowly and steadily 

improving. 

A shipper who fails to properly declare a dangerous goods shipment can 

face serious consequences from a major carrier, particularly if the shipper 

is a business or other operation with an ongoing need for the carrier’s 

services. Two of the major carriers we interviewed may, depending on the 

seriousness of the violation, require a shipper to provide additional 

remedial training in shipping dangerous goods; apply more stringent terms 

for accepting shipments from the shipper; or, in more serious instances, 

permanently terminate the business relationship with the shipper. Officials 

from one of the carriers stated that their company’s requirements for 

remedial training in these instances exceed DOT’s requirements for 

shippers. Similarly, officials from another carrier told us that an 

inadvertent violation of the rules governing the declaration of dangerous 

goods would, in most cases, result in a minimum suspension of 60 days, 

pending the shipper’s completion of training or any other steps the carrier 

chose to require before again accepting packages from that shipper. This 

same carrier’s officials said that when they suspect that a shipper may 

have sent undeclared dangerous goods through their system, they will 

begin an investigation to determine whether the shipper knew or should 

have known that it was doing so. Until the carrier completes that 

investigation, the shipper must agree to let the carrier’s staff open and 

inspect every shipment before accepting it. If this carrier determines that 

the shipper knowingly offered undeclared dangerous goods, it terminates 

its business with that shipper. 

Carriers May Impose Sanctions 

for Shipping Undeclared 

Dangerous Goods 
Page 27 GAO-03-22 Aviation Safety 

To evaluate the effectiveness of and to enforce federal regulations for 

shipping dangerous goods by air, DOT collects data on dangerous goods 

incidents, monitors shippers’ and carriers’ performance, and assesses civil 

penalties. Within DOT, FAA is primarily responsible for enforcing the 

regulations for transporting dangerous goods by air. To ensure that the 

penalties it imposes for violations of dangerous goods regulations are 

appropriate to shippers’ and carriers’ complete compliance histories, FAA, 

together with DOT’s other affected operating administrations, is required 

to consider the compliance history of violators in all modes of 

transportation when assessing penalties against them. This guidance was 

difficult for FAA and others to follow because, until very recently, with the 

exception of RSPA, DOT’s operating administrations were not submitting 

their enforcement data in a timely manner to DOT’s centralized 

enforcement database. Finally, to further ensure that appropriate civil 

penalties are assessed and that similar cases are treated consistently and 

fairly, FAA requires that the reasons for any reduction to a recommended 

civil penalty be documented. Our analysis of FAA’s enforcement case files 

found that FAA is not always documenting its assessments. 

Like DOT, the Postal Service collects data on dangerous goods incidents, 

but it lacks DOT’s authority to assess civil penalties for violations and 

therefore takes few enforcement actions. Legislation proposed by DOT 

would allow the Postal Service to assess civil penalties. 

To monitor and enforce compliance with DOT’s dangerous goods 

regulations, FAA collects data on dangerous goods air incidents and 

discrepancies through its Airport and Air Carrier Information Reporting 

System (AAIRS). RSPA’s regulations define incidents as reportable 

releases of hazardous materials, including those that are unintended and 

unanticipated. “Discrepancies” are defined in the Hazardous Materials 

Regulations (HMR) as instances in which dangerous goods are found to be 

undeclared, misdeclared, or improperly packaged.23 In addition, FAA 

collects data on closed dangerous goods enforcement cases through its 

 23An incident is defined in RSPA’s regulations as an event that results in a reportable 

release of a hazardous material, including unintended and unanticipated releases that 

otherwise require reporting under 49 C.F.R. §171.15 or §171.16. As used in the Hazardous 

Materials Regulations, the term “discrepancies” describes instances of undeclared 

dangerous goods (material found in transportation that was not identified as dangerous 

goods) and instances of misdeclared or improperly packaged dangerous goods. 

For DOT, Inadequate 

Documentation, and 

for the Postal Service, 

Lack of Civil Penalty 

Authority Hamper 

Enforcement of 

Dangerous Goods 

Regulations 

FAA Collects Data to 

Monitor and Enforce 

Compliance 
Page 28 GAO-03-22 Aviation Safety 

Enforcement Information System. (See app. III for more information about 

FAA’s and DOT’s incident and enforcement databases.) 

To ensure that appropriate civil penalties are assessed, FAA’s enforcement 

guidance requires the agency to consider the compliance history of 

violators across all modes of transportation. Until recently, FAA had 

difficulty complying with this guidance because, with the exception of 

RSPA, DOT’s operating administrations were not submitting their closed 

enforcement action data in a timely manner to a central database—the 

Unified Shipper Enforcement Data System (UNISHIP), maintained by 

RSPA. DOT developed this database in response to a 1991 GAO report. 

RSPA is working with DOT’s affected operating administrations to ensure 

the timely submission of enforcement data. On July 17, 2002, the Office of 

the Secretary of Transportation issued a memorandum calling for the 

implementation of required procedures for entering data on dangerous 

goods enforcement actions into UNISHIP. If the database is kept up to 

date, FAA inspectors can obtain compliance information by querying the 

central database. 

Our analysis of FAA’s case files indicates that FAA is not always 

documenting the reasons for reductions to recommended civil penalties, 

as its guidance requires. We found cases in which the proposed civil 

penalty was changed, but either no documentation or incomplete 

documentation was provided to explain the reasons for the reduction. An 

FAA official stated that it was FAA’s policy to include documentation for 

civil penalty changes in the case files. To help ensure that appropriate civil 

penalties are assessed and that similar cases are treated consistently and 

fairly, it is important that FAA document the reasons for any reduction to a 

recommended civil penalty. 

The enforcement process begins when FAA inspectors obtain indication of 

a violation (see fig. 4.). The inspector then determines whether the 

violation warrants administrative action (such as a warning notice or letter 

of correction), legal enforcement action (such as the imposition of a civil 

penalty), or referral for criminal prosecution. When the inspector finds 

that a civil penalty is appropriate, he or she must determine the amount of 

the civil penalty by consulting FAA’s sanction guidance policy. Legal staff 

in the regional office or headquarters then review the strength of the 

evidence, the type of enforcement action, and the amount of the civil 

penalty, if any. Next, a notice of proposed civil penalty is issued that is 

FAA Could Not Readily 

Consider Complete 

Compliance Histories 

When Assessing Penalties 

FAA Is Not Documenting 

Changes to Recommended 

Civil Penalties as Required 
Page 29 GAO-03-22 Aviation Safety 

consistent with the inspector’s report and the review. The alleged violator 

then has an opportunity to reply to the civil penalty assessed. If the alleged 

violator provides convincing evidence that it did not commit the violation, 

FAA dismisses the case. If FAA and the alleged violator agree on an 

appropriate fine, FAA issues an order assessing a civil penalty that binds 

the violator to pay the agreed-upon amount. If no agreement is reached, 

the case is litigated. 
Page 30 GAO-03-22 Aviation Safety 

Figure 3. FAA’s Dangerous Goods Enforcement Process (for Civil Penalty Cases) 

In 15 of the cases we reviewed, the assessed civil penalty differed from the 

proposed civil penalty, but FAA included either no documentation or 

incomplete documentation in the case files to account for the changes. For 

example: 

FAA inspectors obtain evidence of a 

violation.

The inspector then determines whether the 

violation calls for a civil penalty or some other 

enforcement action.

When the inspector finds that a civil penalty is 

appropriate, he or she must determine the amount 

of the civil penalty by consulting FAA's sanction 

guidance policy.

A notice of proposed civil penalty is issued.

If the alleged violator 

provides convincing 

evidence that it did 

not commit these 

violations, FAA 

dismisses the case.

If FAA and the alleged 

violator agree on an 

appropriate fine, FAA 

issues an order 

assessing a civil 

penalty that binds the 

violator to pay the 

agreed-upon amount.

If no agreement is 

reached, the case is 

litigated.

Legal staff in the regional office or headquarters 

then review the case.

Source: Federal Aviation Administration.
Page 31 GAO-03-22 Aviation Safety 

• In 2000, the assessed civil penalty on a chemical company for not properly 

shipping flammable paint was reduced from $75,000 to $15,000, but no 

reason was provided in the file for the change. 

• In 2000, the assessed civil penalty on a paint company for not properly 

shipping flammable paint was reduced from $59,500 to $37,500, but no 

reason was provided in the file for the change. 

In addition, in one case involving the shipment of an oxygen generator by 

an air carrier in 1997, the recommended civil penalty was reduced by 20 

percent, even though oxygen generators were responsible for the ValuJet 

aircraft crash in 1996. This penalty was reduced for reasons that were not 

documented. The reduction was not consistent with the known risks of 

oxygen generators. 

The Postal Service’s standards for mailing dangerous goods are similar to 

DOT’s detailed specifications for packaging, marking, and labeling 

dangerous goods, although the mail is subject to many additional 

limitations and prohibitions, which are imposed by provisions of criminal 

statutes.24 Yet in contrast with DOT, which can assess civil or pursue 

criminal penalties for violations of its standards, the Postal Service can 

only pursue criminal penalties. This leads to little enforcement, because 

many violations are unintentional and involve situations that are 

inappropriate for criminal sanctions. At the same time, the high cleanup 

and damage costs associated with dangerous goods violations are timeconsuming, and damages may be difficult to recover absent authority to 

assess civil penalties. For example, in a 1998 incident, the Postal Service 

incurred costs of $87,000 and the carrier incurred damages of $1.4 million 

when a Priority mail shipment containing four bottles of mercury was 

found to be leaking upon removal from the aircraft. Another costly 

incident occurred in 2000, when 3 gallons of gasoline were illegally 

shipped in a motorcycle gas tank and the tank leaked during the flight, 

requiring the plane to be taken out of service and cleaned. As part of its 

 24The mail is subject to the restrictions in title 18 that prohibit the mailing of any matter 

that is outwardly or of its own force dangerous to life, health, or property, and to 

restrictions defined in the Postal Service’s rules. However, the Postal Service is not subject 

to the Hazardous Materials Transportation Act or to the HMR. We also note that while 

commercial carriers are subject to the federal regulations set forth in title 49, C.F.R., the 

Postal Service operates under title 39, C.F.R. The USPS hazardous material regulations are 

set forth in the Domestic Mail Manual (39 C.F.R. Part 111) and further explained in 

Publication 52, Hazardous, Restricted, and Perishable Mail. 

Postal Service Lacks 

Authority to Impose Civil 

Penalties for Violations 
Page 32 GAO-03-22 Aviation Safety 

proposal to reauthorize the hazardous materials transportation program, 

DOT has included a provision that would allow the Postal Service to 

collect civil penalties and to recover costs and damages for dangerous 

goods violations.25 The Postal Service has been actively working with DOT, 

and it supports this provision. Yet others have raised concerns about 

possible conflicts between the Postal Service’s current law enforcement 

authority and its effect on fair competition between the Postal Service and 

other shippers. The question of whether changes should be made 

regarding the Postal Service’s law enforcement responsibilities continues 

to be discussed as the Congress and others revisit the Postal Service’s 

mission and roles as part of broader postal reform efforts. 

Without statistically valid, generalizable data on the nature and frequency 

of undeclared dangerous goods in air transport, DOT does not know to 

what extent such goods pose a threat to aviation safety, or what resources 

should be allocated to address that threat. Eventually, affordable 

diagnostic screening technologies may enable carriers and DOT to monitor 

dangerous goods shipments efficiently and nonintrusively. Until then, 

greater inspection authority would enable DOT to randomly select and 

open packages; gather statistically valid, generalizable data; and profile 

and target potential violators, thereby possibly enhancing aviation safety. 

A change in the law requiring that shippers consent to the inspection of 

packages shipped by air might help to accomplish these objectives. The 

legislation that DOT has proposed seeking greater inspection authority has 

not to date been limited to the air mode and has not been designed to 

obtain statistically valid data. However, the distinctions between air and 

the other modes that justify more stringent regulations for transporting 

dangerous goods by air, along with the potential benefits to aviation safety 

that could accrue from better data on undeclared air shipments, might 

warrant the development of a proposal that would enable DOT to obtain 

such data. 

The Office of the Secretary’s recent memorandum to the operating 

administrations, calling for the timely submission of closed enforcement 

action data to DOT’s centralized enforcement database, should strengthen 

FAA’s ability to take appropriate enforcement action against violators of 

DOT’s dangerous goods regulations. Provided that the operating 

 25S. 1669 and H.R. 3276, Hazardous Material Transportation Safety Reauthorization Act of 

2001. 

Conclusions 
Page 33 GAO-03-22 Aviation Safety 

administrations continue to follow the memorandum, FAA should be able 

to identify high-risk or problem entities, consider their compliance 

histories in all modes of transportation as its enforcement policy guidance 

requires, and ensure that the penalties it assesses against them are 

appropriate to their histories. Yet FAA still needs to do more to 

demonstrate that it has assessed appropriate civil penalties. Until it fully 

documents the reasons for its assessments, or for changes to its initial 

assessments, as its guidance requires, it cannot provide assurance that the 

penalties are appropriate or that it has handled similar cases consistently. 

In order to strengthen DOT’s enforcement of dangerous goods regulations, 

we recommend that the Secretary of Transportation determine whether 

the unique characteristics of air transport warrant the development of a 

legislative proposal that would enhance DOT’s authority to inspect 

packages shipped by air. 

Depending on the results of his determination, we further recommend that 

the Secretary direct the FAA Administrator to develop a legislative 

proposal that would require shippers to consent to the opening for 

inspection of packages shipped by air. Such a proposal would not only 

enhance FAA’s inspection authority but would also enable FAA to obtain 

statistically valid, generalizable data on the nature and frequency of 

undeclared air shipments of dangerous goods. 

Finally, we recommend that the Secretary direct the Administrator to 

ensure that FAA better communicate and enforce its requirement to 

document the justification for any substantial changes to an initially 

proposed penalty before issuing a final order assessing a penalty. 

We provided DOT and the U.S. Postal Service with a draft of this report for 

their review and comment. We met with DOT officials, including the 

Director of RSPA’s Office of Hazardous Materials Enforcement and the 

Manager of FAA’s Dangerous Goods and Cargo Security Enforcement 

Program, to receive their comments. The U.S. Postal Service provided 

comments via E-mail. DOT and the Postal Service generally agreed with 

our report and provided clarifying and technical comments, which we 

incorporated as appropriate. 

In our draft report, we recommended that the Secretary of Transportation 

direct the DOT administrations that operate and manage a dangerous 

goods program to submit their enforcement data to RSPA’s centralized 

Recommendations for 

Executive Action 

Agency Comments 

and Our Evaluation 
Page 34 GAO-03-22 Aviation Safety 

database. According to our audit work, the administrations were not 

submitting the data and, therefore, FAA could not readily comply with its 

guidance requiring it to consider the compliance history of violators in all 

modes of transportation. However, when we discussed the draft report 

with DOT officials in October 2002, they provided a July 17, 2002, 

memorandum from the Office of the Secretary of Transportation directing 

the operating administrations to submit the data. In addition, in October 

2002, DOT furnished evidence that three of the five administrations 

subsequently provided current data. We therefore deleted this 

recommendation from the final report. DOT agreed with our other 

recommendations, acknowledging that its legislative proposals seeking 

greater inspection authority have not been designed to obtain statistically 

valid data on undeclared shipments of dangerous goods. DOT further 

noted that FAA’s upcoming reauthorization legislation could serve as a 

vehicle for a proposal to expand FAA’s inspection authority, so that the 

agency could obtain better data on undeclared air shipments. While 

indicating that changes to initially proposed civil penalties sometimes 

occur as a result of penalty negotiations, DOT agreed that documenting 

the justification for changes is important for providing assurance that final 

penalties are appropriate and consistent. 

To determine what DOT, the Postal Service, and others involved in the air 

transport of dangerous goods know about undeclared shipments, we 

identified relevant studies and interviewed DOT, Postal Service, industry, 

and industry association officials. We reviewed the documents and reports 

we obtained, visited DOT’s John A. Volpe National Transportation Systems 

Center and FAA’s William J. Hughes Technical Center, and conducted 

additional interviews with the researchers who had carried out critical 

studies. We also interviewed officials at four of the major cargo carriers, 

and conducted site visits at three of their facilities. 

To determine the key mechanisms that the federal government and private 

industry have in place to prevent dangerous goods from compromising 

safety, we interviewed agency and industry officials and federal 

researchers. We also reviewed relevant reports and documents in order to 

identify recent developments in screening technology. 

To determine what DOT and the Postal Service do to foster compliance 

with federal regulations for shipping dangerous goods by air, we 

interviewed agency officials and reviewed reports and documents. We also 

examined FAA’s practices for assessing civil penalties by testing 30 

randomly selected cases from FAA’s Enforcement Information System, 

Scope and 

Methodology 
Page 35 GAO-03-22 Aviation Safety 

which contains a database of over 2,000 cases.26 These cases were 

randomly selected to fairly represent the full range of over 2,000 cases in 

the database. While the number of cases we tested was too small to enable 

us to estimate the extent to which FAA’s enforcement strategy was 

followed in the entire database, these 30 cases permit us to describe the 

types of practices that occur at critical points in the penalty assessment 

process. 

We performed our work from September 2001 through November 2002, in 

accordance with generally accepted government auditing standards. 

As arranged with your office, unless you publicly announce its contents 

earlier, we plan no further distribution of this report until 30 days after the 

date of this letter. At that time, we will send copies to the Chairman and 

the Ranking Minority Member of the House Committee on Transportation 

and Infrastructure, and the Chairman of its Subcommittee on Aviation; 

other appropriate congressional committees; the Secretary of 

Transportation; the Postmaster General, United States Postal Service; the 

Under Secretary of Transportation for Security, Transportation Security 

Administration; the Administrator, Research and Special Programs 

Administration; and the Administrator, Federal Aviation Administration. 

We will also make copies available to others upon request. In addition, the 

report will be available at no charge on the GAO Web site at 

http://www.gao.gov. 

 26The Enforcement Information System contains entries of violations found during 

inspections or through other means (such as police inspections or public complaints) that 

initiate enforcement cases. It contains detailed information on the status and resolution of 

each enforcement case and allows field, regional, and headquarters staff to enter and 

retrieve data. 
Page 36 GAO-03-22 Aviation Safety 

Please call me at (202) 512-2384 if you or your staff have any questions 

about the information in this report. Key contributors to this report are 

listed in appendix IV. 

Sincerely yours, 

Gerald L. Dillingham, Ph.D. 

Director, Physical Infrastructure 
Appendix I: FAA’s Dangerous Goods 

Informational Brochure for Passengers 

Page 37 GAO-03-22 Aviation Safety 

Appendix I: FAA’s Dangerous Goods 

Informational Brochure for Passengers 

There are certain exceptions for personal care, medical

needs, sporting equipment, and items to support

physically challenged passengers. For example:

Hazardous materials are prohibited

in luggage or carried on board.

Signal

flares, sparklers or

other explosives

Drain

cleaners and solvents

Spray cans, butane

fuel, scuba tanks, propane tanks, CO2 cartridges,

self-inflating rafts

Firearms, ammunition, gunpowder, mace, 

tear gas orpepper spray You must declare your hazardous materials to the airline, 

air package carrier, or U.S. Postal Service. Violators of 

Federal Hazardous Materials Regulations (49 CFR Parts 

171-180) may be subject to a civil penalty of up to 

$25,000 for each violation and, in appropriate cases, 

a criminal penalty of up to $500,000 and/or imprisonment 

of up to 5 years.

Dry ice, gasoline-powered tools, 

wet-cell batteries, camping equipment with fuel, radioactive 

materials (except limited quantities), poisons, infectious 

substances

The above list is not all inclusive. For exceptions, read

Fuel, paints, lighter

refills, matches

Personal care items containing hazardous materials

(e.g., flammable perfume, aerosols) totaling no more

than 75 ounces may be carried on board. Contents 

of each container may not exceed 15 fluid ounces.

Matches and lighters may only be carried on 

your person. However, "strike-anywhere" matches, 

lighters with flammable liquid reservoirs and 

lighter fluid are forbidden.

Firearms and ammunition may not be carried by a 

passenger on an aircraft. However, unloaded firearms

may be transported in checked luggage if declared to

the agent at check in and packed in a suitable container.

Handguns must be in a locked container. Boxed small

arms ammunition for personal use may be transported 

in checked luggage. Amounts may vary depending on

the airline.

Dry ice (4 pounds or less) for packing perishables, 

may be carried on board an aircraft provided the 

package is vented.

Electric wheelchairs must be transported in 

accordance with airline requirements. The battery 

may need to be dismounted.

Further restrictions may apply to the above

items. Some items may be shipped as air cargo. 

If you are unsure whether the item you wish

to pack in your luggage or ship by air is

hazardous, contact your airline representative.

Many common items 

used everyday in the home 

or workplace may seem harmless; 

however, when transported by air, they 

can be very dangerous. In flight, variations 

in temperature and pressure can cause items 

to leak, generate toxic fumes or start a fire.

Brochure inside

Brochure outside

Source: Federal Aviation Administration and Research and Special Programs Administration.
Appendix II: Mailability of Dangerous Goods, 

by DOT Class 

Page 38 GAO-03-22 Aviation Safety 

Appendix II: Mailability of Dangerous Goods, 

by DOT Class 

Source: United States Postal Service, Domestic Mail Manual (DMM), C023.
Appendix III: Data Collected by DOT 

Agencies on Dangerous Goods Incidents and 

Enforcement Actions 

Page 39 GAO-03-22 Aviation Safety 

FAA collects data on dangerous goods air incidents, discrepancies, and 

enforcement actions through two databases. Its Airport and Air Carrier 

Information Reporting System (AAIRS) collects basic incident and 

discrepancy information such as the mode, date, and location of the 

incident or discrepancy, the carrier and shipper involved, the hazard class 

of the spilled material, and the consequences of the incident or 

discrepancy. (See table 1.) FAA’s Enforcement Information System (EIS) 

collects information on closed dangerous goods enforcement cases. It 

contains data such as the incident date, the regulations violated, the 

sanction initially recommended, and the final sanction. These enforcement 

data are used to monitor and enforce compliance with DOT’s dangerous 

goods regulations. 

Table 2: DOT Databases Tracking Information on the Air Transportation of 

Dangerous Goods 

Database name 

Database 

custodian Description 

Hazardous Material 

Incident Reporting 

System (HMIRS) 

RSPA DOT’s HMIRS is the primary source of 

national incident data for the federal, state, 

and local government agencies responsible 

for the safety of dangerous goods 

transportation. Carriers of dangerous goods 

supply these data through their reporting of 

dangerous goods incidents. 

Unified Shipper 

Enforcement System 

(UNISHIP) 

RSPA UNISHIP contains information on closed 

enforcement actions taken against shippers 

and freight forwarders in all modes of 

transportation, including air. 

Airport/Air Carrier 

Information Reporting 

System (AAIRS) 

FAA AAIRS has been used since 1996 to track 

inspections of airports and air carrier 

stations. It includes dangerous goods 

incidents (which are also reported to 

HMIRS) and discrepancies (dangerous 

goods discoveries that occur through 

avenues other than faulty packaging, such 

as luggage inspection). 

Enforcement Information 

System (EIS) 

FAA The EIS contains entries of violations found 

during inspections or through other means 

(such as police inspections or public 

complaints) that initiate enforcement cases. 

Source: RSPA and FAA. 

RSPA collects dangerous goods incident and enforcement data through 

two databases. Its Hazardous Materials Incident Reporting System 

(HMIRS) collects dangerous goods incident information across all 

transportation modes, not just the air mode. This information is similar to 

that collected in FAA’s AAIRS database, but it does not include 

Appendix III: Data Collected by DOT 

Agencies on Dangerous Goods Incidents and 

Enforcement Actions 
Appendix III: Data Collected by DOT 

Agencies on Dangerous Goods Incidents and 

Enforcement Actions 

Page 40 GAO-03-22 Aviation Safety 

discrepancies. RSPA tracks closed hazardous materials enforcement cases 

through its Unified Shipper Enforcement System (UNISHIP). This 

database tracks closed enforcement actions across all transportation 

operating administrations, not simply air. 

RSPA collects data on dangerous goods incidents from all transportation 

modes through DOT Form F 5800.1, which captures basic information on 

incidents such as the mode, date, and location of the incident; the carrier 

and shipper involved; the hazard class and shipping name of the spilled 

material; and the consequences of the incident (including deaths, injuries, 

product loss, and damage). RSPA uses the data and the information it 

collects on dangerous goods incidents to (1) evaluate the effectiveness of 

existing regulations, (2) assist in determining the need for regulatory 

changes to cover changing transportation safety problems, and (3) 

determine major problem areas so that attention can be more suitably 

directed to them. In addition, both the government and industry use this 

dangerous goods incident information to chart trends and identify training 

inadequacies and packaging deficiencies. 

In addition to RSPA, UNISHIP serves the enforcement programs of the 

Federal Aviation Administration, the Federal Railroad Administration, the 

Federal Motor Carrier Safety Administration, the U.S. Coast Guard, and 

the Inspector General by providing a history of compliance for the 

companies contained in the system. 
Appendix IV: GAO Contacts and Staff 

Acknowledgments 

Page 41 GAO-03-22 Aviation Safety 

Gerald L. Dillingham, Ph.D., (202) 512-2834 

Belva M. Martin, (202) 512-2834 

In addition to those named above, Elizabeth R. Eisenstadt, Arthur L. 

James, Bert Japikse, David Laverny-Rafter, Bill MacBlane, Kieran 

McCarthy, Richard Scott, and Katherine Wulff made key contributions to 

this report. 

Appendix IV: GAO Contacts and Staff 

Acknowledgments 

GAO Contacts 

Acknowledgments 

(540004) 
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