Table B-2c. Estimated Standard Errors for Hazardous Material Shipment Characteristics by Hazard Class for the United States: Percentage of Total for 2012 and 2007

Monday, July 13, 2015

(Estimates are based on data from the 2012 and 2007 Commodity Flow Surveys)

Hazard class and description	Value— standard error		Tons— standard error		Ton-miles (1)— standard error
	Value— standard error		Tons— standard error		Ton-miles (1)— standard error
	2012	2007	2012	2007	2012	2007
Total	0.0	0.0	0.0	0.0	0.0	0.0
Class 1, Explosives	0.2	0.2	Z	0.0	0.1	0.0
Class 2, Gases	0.3	0.8	0.4	0.9	0.9	1.8
Class 3, Flammable and combustible liquid	0.6	1.2	0.4	1.1	1.5	2.0
Class 4, Flammable solid; spontaneously combustible material; dangerous when wet material	Z	0.1	0.1	0.2	0.5	0.3
Class 5, Oxidizers and organic peroxides	Z	0.0	0.1	0.1	0.4	0.4
Class 6, Toxic materials and infectious substances	0.1	0.4	0.1	0.1	0.2	0.4
Class 7, Radioactive material	0.2	0.3	S	0.0	Z	0.0
Class 8, Corrosive material	0.2	0.2	0.4	0.4	1.0	1.7
Class 9, Miscellaneous hazardous material	0.2	0.2	0.3	0.2	0.9	0.8

KEY: S = Withheld because estimate did not meet publication standards.

Z = Rounds to zero.

(1) Ton-miles estimates are based on estimated distances traveled along a modeled transportation network. See “Mileage Calculations” section for additional information.

NOTES: The Introduction and appendixes give information on confidentiality protection, sampling error, nonsampling error, sample design and definitions. Links to this information on the Internet may be found at <www.census.gov/econ/cfs>.

SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics and U.S. Department of Commerce, U.S. Census Bureau, 2012 Economic Census: Transportation Commodity Flow Survey, December 2014.