Hazardous Materials Information System
(Data are collected from the entire population of interest)
Data Scope
Data includes spills, releases, or other incidents involving hazardous
materials in commerce during the course of transportation. All modes of
transportation are included except pipeline and bulk marine transportation.
Data represent a census of all incidents reportable to the U.S. Department
of Transportation (DOT). U.S. federal regulations require all spills meeting
the following criteria to be reported, in writing, to DOT's Office of Hazardous
Materials Safety:
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As a direct result of hazardous materials:
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a person is killed or receives injuries requiring hospitalization; or
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estimated property damage exceeds $50,000; or
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an evacuation of the general public lasts for one or more hours; or
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a major transportation artery or facility is closed for one or more hours;
or
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the operational flight pattern or routing of an aircraft is altered; or
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Fire, breakage, spillage, or suspected contamination occurs involving shipment
of radioactive materials or infectious substances; or
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There as been a release of a marine pollutant exceeding 450 L or 400 kg;
or
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Any unintentional release of a hazardous material from a package or any
quantity of hazardous waste discharged during transportation.
Data Collection
Methods - Data are collected by the carrier involved in each
reportable incident and submitted to DOT's Office of Hazardous Materials
Safety (OHM) on Form DOT F 5800.1. Carriers are required by regulation
to report incidents and face significant penalties for failing to do so.
Schedule - Incident reports are received continuously by OHM.
Carriers are required to submit incident reports to DOT within 30 days
of the incident. Once received by OHM, it takes approximately one month
for incident reports to be processed and verified. The data are then made
available in the HMIS database during the next monthly update.
Response Rates - This HMIS contains all incidents reported to
DOT. Any incident discovered by OHM to be reportable and for which an incident
report was not submitted is referred to the Office of Hazardous Materials
Enforcement, which ensures compliance with the reporting requirement. While
OHM acknowledges that there is some level of under reporting, it believes
that the under reporting is limited to small, non-serious incidents. As
incident severity increases, it is more likely that the incident will come
to OHM's attention and will ultimately be reported. Additionally, the reporting
requirements were recently extended to intrastate highway carriers and
the response rate from this new group is expected to increase over time.
Nonsampling Errors
Nonsampling errors are primarily due to nonreporting, incomplete data
submissions, or the data entry process. Quality control procedures are
used to minimize these errors and are periodically reviewed and updated.
Nonsampling errors should not have a significant impact on many interpretations
of the data, but the impact will vary depending on the data used. Data
on serious incidents have a much lower error rate than do minor or very
small incidents, yet most incidents in the HMIS are not serious. No efforts
have been made to date to quantify the level of nonsampling error.
Nonentry Error - Some reports submitted to DOT do not meet the
reporting criteria and are not included in the incident database. However,
these reports are included in a supplemental database for tracking purposes.
The only other source of missing records is non-reporting. RSPA defines
serious incidents as incidents that involve: a fatality or major injury
due to a hazardous material; closure of a major transportation artery or
facility or evacuation of six or more persons due to the presence of a
hazardous material; or a vehicle accident or derailment resulting in the
release of a hazardous material. Serious incidents often elicit media coverage
or trigger reporting requirements for other modes or agencies. This exposure
makes it easier for OHM to determine if the incident was not reported.
OHM routinely cross-checks incident reports against other sources of incident
data, such as the telephonic reporting system for incidents requiring immediate
notification provided to the National Response Center (NRC), databases
maintained by the Federal Railroad Administration (FRA) and Federal Highway
Administration (FHWA), and media reports to identify incidents that are
not reported. The extent to which some minor incidents are not reported
is not known.
Duplicate Entry Error - While only the carrier of a hazardous
material in transportation is required to report incidents to DOT, shippers
and other interested parties occasionally submit incident reports. It is
also possible that duplicate incident reports are submitted by the same
carrier for the same incident. Even more rare are incidents involving more
than one carrier of hazardous materials resulting in the submission of
multiple reports for the incident. Extensive automated routines and additional
review identify most duplicate incident reports and they are combined or
deleted, as appropriate.
Missing Data Error - Because the incident reports are prepared
by the carrier, some data may be missing from the report. In many cases,
the reporter left a data field empty, rather than providing a 'zero' or
'none' response. In other cases, the reporter did not have the requested
information and chose to skip the field. The HMIS captures information
for many fields indicating whether the response was provided by the reporter
or when missing elements were generated or determined by OHM. When certain
data are omitted, the reporter is contacted to provide complete information.
Response/Measurement Error - Since carriers are required to complete
the incident reports themselves, it is possible that, in an effort to reduce
exposure to liability, they provide incomplete or misleading information.
The requirement to report incidents within 30 days may also contribute
to incomplete or inaccurate data, as complete information for an incident
may not readily be available by the due date. Although there exists some
overlap in reporting requirements with other modes and other agencies,
the data they collect does not provide sufficient overlap to measure data
quality, only to identify potential cases of non-reporting.
Coding/Recording Error - Coding errors can occur, but they are
typically discovered during quality checks of the database or internal
data analysis.
Noncoverage Error - There is no known noncoverage error. However,
pipeline and bulk marine incidents are not reportable to the HMIS. Data
on these incidents are maintained by the Office of Pipeline Safety and
the U.S. Coast Guard, respectively.
Verification and Validation
Verification and validation occurs in several places in the data reporting
and collection process. Incident reports are manually examined and coded
to determine the appropriate values for storage in the HMIS. For certain
serious incidents, the reporter is contacted to verify important information.
Additional telephone data collection occurs under certain circumstances,
such as verifying that all reported injuries and fatalities were due to
the hazardous material and not, for example, the impact from a vehicular
crash. Data entry is performed by individuals who are able to identify
inconsistencies introduced or missed in the coding process. The data entry
software further helps to ensure data quality and consistency with pick
lists and numerous logic checks. Before final release into the HMIS, additional
quality assurance routines are run against the data. Finally, internal
data analysis and informal review of published data by external parties,
including the reporting carriers, help to identify the infrequent errors
that are not identified and corrected before the data are released.
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