Hazardous materials movement through the Nation’s transportation network in 2007 remained relatively unchanged 

from 2002 measures, according to data from the 2007 

Commodity Flow Survey (CFS), released in 2010. The estimated 2.2 billion tons of hazardous materials carried by all 

modes of transportation is about the same as the estimated 

tonnage from the prior CFS in 2002. However, the value of 

those shipments more than doubled, from $660 billion to 

$1,448 billion, driven primarily by the increase in the price 

of refined petroleum products and other basic commodities. 

Slightly more than half (54 percent) of hazardous material 

tonnage is moved via trucks over the Nation’s highways. 

Pipeline is the next most used carrier of hazardous materials, handling 28 percent of the tonnage, while the other 

modes each accounted for 7 percent or less of total hazardous material tonnage. 

Hazardous Material Classes

There are nine classes of hazardous materials. Flammable 

Liquids (Hazard Class 3) represented the bulk of hazardous 

materials transported. Of the 2.2 billion tons of hazardous 

materials shipped, 1.8 billion tons were Flammable Liquids, 

primarily consisting of refined petroleum products. Shipments of Hazard Class 3 materials accounted for 182 billion 

(56.1 percent) of the total 323 billion hazardous materials 

ton-miles generated in 2007. Shipments of Hazard Class 

2 (Gases) comprised 251 million tons, and their transport 

amounted to 55 billion ton-miles. Corrosive Materials (Hazard Class 8) shipments totaled 114 million tons, generating 

44 billion ton-miles. Table 1 shows shipments by hazardous material class.

Some hazardous materials are additionally designated as 

“Toxic by Inhalation” (TIH), which includes gases and volatile liquids that are toxic when inhaled and pose additional 

risk when transported. In 2007, shippers sent 27 million 

tons of TIH materials that accounted for 10 billion ton-miles. 

Most hazardous materials are designated in the Code of 

Federal Regulations (CFR) as requiring shipment in Packing Groups I, II, or III. Packing Group I requires, by regulation, the most rigorous packaging for transport. In 2007, 

shippers sent 586 million tons of Packing Group I materials, 

generating 72 billion ton-miles. 

Shipments by Mode

Trucks transported the largest volume of hazardous materials through the Nation’s transportation system, moving 

1.2 out of 2.2 billion tons of hazardous materials. These 

shipments accounted for 104 billion highway ton-miles, out 

of the total 323 billion ton-miles moved by all modes. CFS 

data for the highway mode is particularly important because 

it represents the sole source of national data for hazardous 

materials transported by truck. 

Overall, the truck mode moved 53.9 percent of hazardous 

materials tonnage in 2007. Private trucking carried 31.7 percent, and for-hire trucking carried 22.2 percent. Hazardous 

materials shipments transported solely by truck represented 

50 percent or more of the tonnage in every hazard class 

SR-026

January 2011

Hazardous Materials Highlights – 2007 Commodity 

Flow Survey

by Ron Duych, Chester Ford, and Hossain Sanjani

Special Report

RITA Bureau of Transportation Statistics

About the Commodity Flow Survey

Survey data cited in this report are from the 2007 Economic 

Census released in July 2010. The Commodity Flow Survey 

(CFS) is the primary source of national and State-level data 

on domestic freight shipments by American establishments in 

mining, manufacturing, wholesale, auxiliaries, and selected 

retail industries. Data are provided on the types, origins and 

destinations, values, weights, modes of transport, distance 

shipped, and ton-miles of commodities shipped. The CFS is a 

shipper-based survey and is conducted every 5 years as part 

of the Economic Census. It provides a modal picture of national freight flows and represents the only publicly available 

source of commodity flow data for the highway mode. Prior to 

2007, the CFS was conducted in 1993, 1997, and 2002. CFS 

data and publications can be found at http://www.bts.gov/publications/commodity_flow_survey/.
BTS Special Report

2

except Class 6 (Toxic Materials and Infectious Substances), 

which had roughly half of its tonnage transported by rail. 

(See table 1 for a list of classes.) The remaining hazardous 

materials tonnage recorded in the 2007 CFS was transported by pipeline—28.2 percent; water—6.7 percent; rail—5.8 

percent; and multiple, other, and unknown modes—5.4 

percent (table 2).

The 2007 CFS shows that 32.2 percent of all hazardous 

materials ton-miles are attributed to truck, 28.5 percent to 

rail, and 11.5 percent to water, with other modes handling the 

remainder (table 3).

Hazardous Materials Shippers

Industry subsectors and groups under the North American Industry Classification System (NAICS) that are major 

hazardous materials shippers include the Petroleum and 

Coal Products Manufacturing industry (NAICS 324), which 

transported 56.0 percent of its hazardous materials tonnage 

via pipeline and 21.3 percent by truck, and the Petroleum 

and Petroleum Products Merchant Wholesalers industry 

(NAICS 4247), which transported 90.5 percent of its hazardous materials tonnage by truck. The Chemical Manufacturing 

industry (NAICS 325) moved 39.5 percent of its hazardous 

materials tonnage by truck, 25.3 percent by rail, and 19.7 

percent via pipeline (table 4).

Other Hazardous Materials Shipment 

Characteristics

The movement of hazardous materials through the U.S. 

transportation system represents almost 18 percent of total 

tonnage for all freight shipments as measured by the CFS. 

Hazardous materials ton-mileage represents about 10 percent of the CFS national total (table 5).

The majority of hazardous materials transportation originates 

in a limited number of States. There are 10 States responsible for initiating the transportation of approximately two-thirds 

of both the tonnage and ton-miles associated with hazardous 

materials transportation across our Nation. Texas was the 

State that had the greatest amount of hazardous materials 

shipments by tonnage as both an origin and destination in 

the 2007 and 2002 CFS, due in large part to the concentration of the petro-chemical industry located there. Louisiana 

and California represented the next two States with the 

greatest amount of hazardous materials shipments by tonnage. 

Comparisons With Prior Surveys

The estimated total of 2.23 billion tons of hazardous materials shipments reported in the 2007 CFS is not significantly 

different from the estimated 2.19 billion tons reported in the 

Table 2: Hazardous Materials Shipment Tonnage 

Shares by Mode in 2007

Mode of transportation Percentage of Tons

All modes 100.0

Truck 53.9

Pipeline 28.2

Water 6.7

Rail 5.8

Multiple modes 5.0

Other and unknown modes 0.4

NOTES: The total includes shipments via the air mode. However, an 

individual estimate for the air mode cannot be published because it does 

not meet the standard for release due to variability.

SOURCE: Research and Innovative Technology Administration and U.S. 

Census Bureau, 2007 Commodity Flow Survey, Hazardous Materials, 

Table 1c, available at http://www.bts.gov/publications/commodity_flow_

survey/.

Table 1: Hazardous Materials Shipment Characteristics by Hazard Class in 2007

Hazard class and description

Value

(million $)

Tons 

(thousands)

Ton-miles 

(millions)

Average miles 

per shipment

Total 1,448,218 2,231,133 323,457 96

Class 1, Explosives 11,754 3,047 911 738

Class 2, Gases 131,810 250,506 55,260 51

Class 3, Flammable liquids 1,170,455 1,752,814 181,615 91

Class 4, Flammable solids 4,067 20,408 5,547 309

Class 5, Oxidizers and organic peroxides 6,695 14,959 7,024 361

Class 6, Toxic (poison) 21,198 11,270 5,667 467

Class 7, Radioactive materials 20,633 515 37 S

Class 8, Corrosive materials 51,475 114,441 44,395 208

Class 9, Miscellaneous dangerous goods 30,131 63,173 23,002 484

KEY: S = Estimate does not meet publication standards because of high sampling variability or poor response quality.

SOURCE: Research and Innovative Technology Administration and U.S. Census Bureau, 2007 Commodity Flow Survey, 

Hazardous Materials, Table 2a, available at http://www.bts.gov/publications/commodity_flow_survey/.
BTS Special Report

3

Table 3: Hazardous Materials Shipments by Mode in 2007

Mode of transportation

Value 

(million $)

Tons

(thousands)

Ton-miles

(millions)

Average miles 

per shipment

All modes 1,448,218 2,231,133 323,457 96 

Truck 837,074 1,202,825 103,997 59 

 For-hire truck 358,792 495,077 63,288 214 

 Private truck 478,282 707,748 40,709 32 

Rail 69,213 129,743 92,169 578 

Water 69,186 149,794 37,064 383 

Air (includes truck and air) 1,735 S S 1,095 

Pipeline 393,408 628,905 S S 

Multiple modes 71,069 111,022 42,886 834 

 Parcel, U.S.P.S. or courier 7,675 236 151 836 

 Other multiple modes 27,739 56,750 17,297 233 

Other and unknown modes 6,534 8,489 1,466 58 

KEY: S = Estimate does not meet publication standards because of high sampling variability or poor response quality.

SOURCE: Research and Innovative Technology Administration and U.S. Census Bureau, 2007 Commodity Flow Survey, 

Hazardous Materials, Table 1a, available at http://www.bts.gov/publications/commodity_flow_survey/.

Table 4: Hazardous Materials Shipment Characteristics for Selected NAICS Codes in 2007

NAICS 

Code NAICS Code Description

Tons Ton-Miles

Total 

(thousands)

Hazardous 

(thousands)

Hazardous share 

(percent)

Total 

(thousands)

Hazardous 

(thousands)

Hazardous share 

(percent)

Total 12,543,425 2,231,133 17.8 3,344,658 323,457 9.7

324

Petroleum and coal products 

manufacturing 1,415,099 930,698 65.8 207,148 128,090 61.8

325 Chemical manufacturing 594,262 248,941 41.9 279,917 101,050 36.1

4246

Chemical and allied products merchant wholesalers 119,971 64,533 53.8 31,344 12,813 40.9

4247

Petroleum and petroleum products 

merchant wholesalers 846,636 803,894 95.0 52,112 39,482 75.8

45431 Fuel dealers 48,438 47,817 98.7 1,784 1,761 98.7

551114

Corporate, subsidiary, and regional 

managing offices 250,262 72,893 29.1 80,199 17,764 22.1

-- All other surveyed industries 9,268,757 62,357 0.7 2,692,154 22,497 0.8

NOTE: NAICS codes shown had the highest estimated weight without considering the sampling variability.

SOURCE: Research and Innovative Technology Administration and U.S. Census Bureau, 2007 Commodity Flow Survey, Hazardous Materials, Table 17; 

and 2007 Commodity Flow Survey, U.S. Report, table 10, available at http://www.bts.gov/publications/commodity_flow_survey/.
BTS Special Report

4

Table 5: Hazardous Versus Nonhazardous Materials Shipment Characteristics by Mode of 

Transportation in 2007

Mode of transportation

Tons Ton-miles

Total 

(thousands)

Hazardous 

Percentage

Nonhazardous 

Percentage

Total 

(millions)

Hazardous 

Percentage

Nonhazardous 

Percentage

All modes 12,543,425 17.8 82.2 3,344,658 9.7 90.3

Truck 8,778,713 13.7 86.3 1,342,104 7.7 92.3

 For-hire truck 4,075,136 12.1 87.9 1,055,646 6.0 94.0

 Private truck 4,703,576 15.0 85.0 286,457 14.2 85.8

Rail 1,861,307 7.0 93.0 1,344,040 6.9 93.1

Water 403,639 37.1 62.9 157,314 23.6 76.4

Air (includes truck and air) 3,611 S 90.2 4,510 S 96.1

Pipeline 650,859 96.6 3.4 S S S

Multiple modes 573,729 19.4 80.6 416,642 10.3 89.7

 Parcel, U.S.P.S. or courier 33,900 0.7 99.3 27,961 0.5 99.5

 Other multiple modes 113,841 49.8 50.2 46,402 37.3 62.7

Other and unknown modes 271,567 3.1 96.9 33,764 4.3 95.7

KEY: S = Estimate does not meet publication standards because of high sampling variability or poor response quality.

SOURCE: Research and Innovative Technology Administration and U.S. Census Bureau, 2007 Commodity Flow Survey, Hazardous Materials, Table 

4, available at http://www.bts.gov/publications/commodity_flow_survey/.

2002 CFS. However, the estimated value of hazardous materials shipped more than doubled from $660 billion in 2002 

to $1,448 billion in 2007, principally due to an increase in 

the price of refined petroleum products and basic commodities classified as hazardous materials.

The usage of modes of transportation for shipments of 

hazardous materials in 2007 was similar to that in 2002. In 

2007, 53.9 percent of hazardous materials tonnage was 

carried by truck, compared to 52.9 percent in 2002. Similarly pipeline, the mode that transported the second-largest 

volume of hazardous materials in 2007, had a share of 28.2 

percent in 2007, compared to a share of 30.2 percent in 

2002. Due to methodological changes in mileage calculations, much of the tonnage previously identified as moving 

solely by the water mode has shifted to multiple mode classifications, in which water is part of the modal combination. 

The same States that accounted for the most hazardous 

material shipments tonnage and ton-miles in 2002 were 

also the leading States in 2007 (see figure 1).

Efforts were undertaken with the 2007 CFS to improve the 

reliability of the estimates for hazardous materials through 

the targeting and oversampling of hazardous materials 

shippers. This “oversampling” of hazardous materials shippers, together with a 2007 CFS sample size of 102,369 

establishments, resulted in 5.6 percent of the 4.9 million 

2007 CFS shipment records being classified as a hazardous materials shipment, compared to 4.9 percent of 2.6 

million shipment records from a sample of 51,005 establishments in the 2002 CFS being designated as a hazardous 

materials shipment.

Application of CFS Hazardous Materials Data

Hazardous materials shipment data collected in the CFS 

allow for the identification of hazardous material flows by 

mode over our Nation’s transportation network. These data 

provide information that is critical for conducting hazardous 

materials transportation safety risk analyses and security 

assessments. Hazardous materials data produced from the 

CFS represent national benchmarks of the type, quantity, 

and distance of hazardous materials transported by mode 

in the United States. These data are used in policy development, the rule making process, program planning and 

identifying emergency response and preparedness needs, 

and can also be used to establish national estimates of 

daily hazardous material shipments.

Hazardous materials data from the CFS are used to assess 

the safety of hazardous materials transportation. CFS data 

employed as denominator values when joined together with 

the numerator values of hazardous materials accidents and 

incidents can be used to quantify the level of risk associated with transporting hazardous materials.

CFS hazardous materials data fill a need for benchmark 

national hazardous material transportation flow data. Data 

on the flows of hazardous materials in the rail and water 

modes are collected in other data sets, but are not necessarily publicly available and do not provide a complete nationwide assessment of hazardous materials transportation. 

CFS hazardous materials data provide national estimates 

of hazardous materials transportation flows across all 

modes and combinations of modes.
BTS Special Report

5

Figure 1: Hazardous Materials Tonnage by Originating State, 2007

Hazardous Materials Transportation Regulation

The safety of transporting hazardous materials has long been 

an area of concern to the Federal Government. Legislation regulating the transportation of explosives and flammable materials 

was first enacted in the mid-nineteenth century. In 1908, Congress passed the Explosives and Combustibles Act, authorizing 

the Interstate Commerce Commission to issue regulations covering the packing, marking, loading, and handling of explosives 

and other dangerous substances in transit. 

The Federal statute known as the Hazardous Materials Transportation Act (HMTA) of 1974, signed into law in 1975, expanded the role of the U.S. Department of Transportation in regulating the safety of hazardous material transportation. The HMTA 

states that when the Secretary of Transportation finds that 

transportation of a commodity of a particular quantity and form 

poses an unreasonable risk to the health and safety or property 

of the public, the commodity is to be designated as a hazardous 

material.

The regulations identifying various commodities as hazardous 

materials and specifying the requirements for their transport are 

codified in the Code of Federal Regulations (CFR) Title 49 Parts 

100 to 185. A table listing over 3,000 proper shipping names and 

corresponding hazmat identification numbers along with specific 

transportation requirements is shown in 49 CFR 101. 

The hazmat identification number is a four-digit number (also 

known as the United Nations/ North American, or UN/NA number) and is assigned to each listed hazardous material in the 

hazardous materials table. The four-digit hazmat ID numbers 

are grouped into 21 divisions that are categorized by 9 distinctive Hazard Classes. This regulatory structure is now universal, 

having been developed and implemented by international committees organized under the authority of the United Nations.

Building on this existing detailed and hierarchical regulatory 

scheme—while at the same time collecting shipment data by 

the Standard Classification of Transported Goods (SCTG) 

codes—the CFS compiles a robust dataset of hazardous materials estimates by asking hazardous materials shippers to enter 

a four-digit UN/NA identification number on the CFS questionnaire. These data allow for the production of separate CFS 

analyses including a Hazardous Materials Report that displays 

hazardous material data sorted by hazard class, division, and 

selected hazmat ID numbers by the standard CFS characteristics of mode, value, tons, ton-miles, and distance shipped. 

Although there are alternative data sources for obtaining data 

on hazardous materials shipments in the rail and water modes, 

CFS hazardous materials data is the only publicly available 

source of hazardous materials flow data for the highway and air 

modes, as well as multiple-mode combinations.
BTS Special Report

6

About This Report 2007 CFS Publications

•	 2007 Commodity Flow Survey, U.S. Report

•	 2007 Commodity Flow Survey, Hazardous Materials Report

•	 2007 Commodity Flow Survey, Export Report

•	 2007 Commodity Flow Survey, State Summaries

CFS data and publications can be found at http://

www.bts.gov/publications/commodity_flow_survey.

This report was prepared by Ron Duych, a Senior 

Transportation Specialist in the Bureau of Transportation Statistics (BTS), Chester Ford, a Transportation Industry Analyst in BTS, and Hossain Sanjani, a 

Survey Statistician in BTS. BTS is a component of the 

U.S. Department of Transportation’s Research and Innovative Technology Administration (RITA).

This special report is based on data from the 2007 and 

2002 Commodity Flow Surveys.

For copies of the BTS Special Report or questions 

about this or other BTS reports, call 1-800-853-1351, 

email RITAinfo@dot.gov, or visit www.bts.gov.