"Table 1-53 U.S. Hazardous Materials Shipments by Hazard Class, 1997 ",,,,,,,
,,,,,,,Average 
,Value,,Tons,,Ton-miles,,miles per 
Hazard Class and Description,($ billion),Percent,(thousands),Percent,(millions),Percent,shipment
,,,,,,,
Class 1.  Explosives, 4.3 , 0.9 , 1.5 , 0.1 , S , S , 549 
Class 2.  Gases, 40.9 , 8.8 , 115.0 , 7.3 , 21.8 , 8.3 , 66 
Class 3.  Flammable liquids, 335.6 , 72.0 ," 1,264.3 ", 80.8 , 160.0 , 60.6 , 73 
Class 4.  Flammable solids, 3.9 , 0.8 , 11.8 , 0.8 , 9.6 , 3.6 , 838 
Class 5.  Oxidizers and organic peroxides, 4.5 , 1.0 , 9.2 , 0.6 , 4.5 , 1.7 , 193 
Class 6.  Toxics (poison), 10.1 , 2.2 , 6.4 , 0.4 , 2.8 , 1.1 , 402 
Class 7.  Radioactive materials, 2.7 , 0.6 , 0.9 , 0.1 , RZ , RZ , 445 
Class 8.  Corrosive materials, 40.4 , 8.7 , 91.6 , 5.9 , 41.2 , 15.6 , 201 
Class 9.  Miscellaneous dangerous goods, 23.9 , 5.1 , 65.3 , 4.2 , 22.7 , 8.6 , 323 
  Total, 466.4 , 100.0 ," 1,565.2 ", 100.0 , 263.8 , 100.0 , 113 
KEY:  S = data were not published because of high sampling variability or other reasons; RZ = less than 1 unit of measure or equal to zero.,,,,,,,
,,,
NOTE:  Numbers and percents may not add to totals due to rounding.,,,
,,,
"SOURCE:  U.S. Department of Transportation, Bureau of Transportation Statistics and  U.S. Department of Commerce, Census Bureau, 1997 Economic Census 1997 Commodity Flow Survey, Hazardous Materials (Washington, DC:  December 1999), table 2. ",,,