Incidence data

Commonly, there are components that are not in any database of failure rates, or the data do not apply for the environment or test and maintenance at your plant. In addition, site specific data may be needed for regulatory purposes or for making the plant run safer and better. For both cases there is a need for calculating failure rate data from incident data, and the mechanics of database preparation and processing. 

The fact that the model connecting error types with their causes may change as a result of gaining further experience with the data collection system means that the informahon gathered on the PIFs in a situation may also change. For example, if incident data indicates the neglect of safety procedures because of production pressures, then the questions relating to this area wUl need to be extended. 

The personnel responsible for the collection and analysis of incident data vary in different organizations. One common practice is to assign the responsibility to an investigation team which includes the first line supervisor, a safety specialist and a plant worker or staff representative. Depending on the severity of an incident, other management or corporate level investigation teams may become involved. 

Individuals involved in accidents where error was a possible factor can have access to a computer which will allow them to provide information on a confidential basis. Although portable computers have not yet made a significant impact on incident data collection, there is clearly considerable potential in this area. 

This report is by Battelle Columbus Division to the Line Pipe Research Supervisory Committee of the American Gas Association. It presents an analysis of statistical data obtained from reports of lea)c or rupture (service) incidents and test failures in natural gas transmission and gathering lines over the 14.5 year period from 1970 through June, 1984. All gas transmission companies were required to notify the Office of Pipeline Safety Operations in the event of a "reportable" incident, as defined by the Code of Federal Regulations. The purpose of the study is to organize the reportable incident data into a meaningful format from which the safety record of the industry can be assessed. 

Bockholts, P. Collection and Application of Incident Data. /. Chem. E. Symp., Series 80, Kll-K21, 1983. 

To determine maximum individual risk, generic frequency data are required for explosion events for Process Units 1 and 2. For Process Unit 1, incident data were available from the unit licenser identifying three explosions in approximately 15,000 operating years, for an explosion frequency of 2.0 x 10-4 per year. For Process Unit 2, a fault tree analysis of the nitrogen vessel brittle fracture event had been conducted as part of an unrelated project. That study concluded that the frequency of brittle fracture failure of the nitrogen vapor storage vessel was 5x10"4 per year. 

In the first few years, there was a known underreporting, bur reliable cancer incidence data from 1955 and up to date are available (Cancer Registry, 1978). 

United States General Accounting Office. (2000). "Adverse Drug Events The Magnitude of Health Risk is Uncertain Because of Limited Incidence Data." GAO/HEHS-OO-21. 

In spite of its current popularity in the pharmaceutical industry, the use of two control groups is opposed by some statisticians on the grounds that a significant difference between the two groups may indicate that the study was compromised by excessive, uncontrolled variation. Haseman et al. (1986), however, analyzed tumor incidence data from 18 color additives tested in rats and mice and found that the frequency of significant pairwise differences between the two concurrent control groups did not exceed that which would be expected by chance alone. 

For all agents of concern in occupational toxicology (except therapeutics), the major route by which the general population is most frequently exposed is the percutaneous (dermal) route. Brown (1980) has previously reviewed background incidence data on pesticides, for example, that show such exposures to be common. Dermal (or topical) drugs are not as common, but are certainly numerous. 

In 1985, the United States Federal Register recommended that the analysis of tumor incidence data be carried out with a Cochran-Armitage (Armitage, 1955 Cochran, 1954) trend test. The test statistic of the Cochran-Armitage test is defined as this term ... 

Reactive hazards are diverse. The reactive incident data analyzed by CSB included ... 

Incident data collected by OSHA and EPA provide no functional capability to track reactive incidents so as to analyze incident trends and develop preventive actions at a national level. 

Existing sources of incident data are not adequate to identify the number, severity, and causes of reactive incidents or to analyze incident frequency trends. 

Suggested improvements for sharing reactive chemical test data, incident data, and lessons learned. 

Numerous types of chemical reactions pose potential hazards. Literature and incident data highlight the hazards of common industrial reactions, such as polymerization, decomposition, acid-base, oxidation-reduction (redox), and reactions with water. Polymerization and decomposition can be classified as self-reactions because they often involve just one chemical substance. However, other... 

Sources of incident data include a variety of public-domain databases, technical literature, and news accounts (Appendix E). Sources are categorized in Appendix E as reviewed only if incident data did not meet the CSB definition of reactive chemical incident (Section 1.3). 

Although the statistics provided in Section 3.3 concerning the number and severity of reactive incidents are grave, existing sources of incident data are inadequate to identify the number, severity, frequency, and causes of reactive incidents. The following limitations affected CSB analysis of incident data ... 

No single data source provides a comprehensive collection of chemical incidents from which to retrieve or track reactive incident data... 

It is difficult to identify causes and lessons learned in existing sources of process safety incident data because industry associations, government agencies, and academia generally do not collect this information. 

The results of the CSB incident data analysis are acknowledged as representing only a sampling of recent reactive incident data. This limitation precludes CSB from drawing statistical conclusions on incidence rates or inferring trends in the number or severity of incidents. However, despite these limitations, the data can be used to illustrate the profile and causes of reactive incidents. 

CSB analyzed incident data in terms of the chemicals published in NFPA Standards 49 and 325. The data show that only about 10 percent of the 167 known incidents involved chemicals that were rated NFPA 3 or 4 (Figure 15). NFPA not rated or 0 accounts for nearly 60 percent of the data.. (Both the BPS and the Morton incidents involved chemicals that were not rated by NFPA.)... 

Figure 15. NFPA instability rating analysis (formerly reactivity rating) of incident data, 1980-2001.

The CSB incident data were analyzed to determine whether the chemicals involved were considered highly hazardous under the OSHA PSM Standard. For the purposes of analyzing the data, CSB determined if a chemical was covered by OSHA PSM by identifying whether it was listed in PSM or was covered as a flammable chemical by OSHA definition.38... 

CSB was unable to determine from the incident data if a process was PSM covered.39... 

As supported by the CSB incident data, two elements are particularly relevant to reactive hazards-Process Safety Information (PSI 29 CFR 1910.119 [d]) and Process Hazard Analysis (PHA 29 CFR 1910.119... 

Incident data in Section 3.0 illustrate that reactive hazards are broader than the hazardous effects of potential inadvertent mixing of different materials. ... 

CSB incident data were analyzed with respect to coverage under the EPA RMP regulation ... 

---