Tier 1 and Tier 2 process safety events by business activity
Measurement answer
What this metric measures
Number of Tier 1 and Tier 2 process safety events, disaggregated by oil-and-gas business activity.
Specification
Metric specification
- Result format
- Structured table
- Unit
- number — source-defined reporting unit
- Reporting basis
- Reporting period disclosed by the organisation
- Aggregation
- Count of Tier 1 and Tier 2 process safety events, disaggregated by business activity
- Pillar
- Environmental
- Topic
- Changes to nature
- Controlled domain
- Pollution
- Entity type
- Metric
Reporting boundary
Process safety events within the organisation's disclosed oil-and-gas business activities and reporting boundary
Verified source occurrences
Framework coverage
This is one canonical metric. The bindings below show every verified framework occurrence without creating duplicate metric pages. Edition, disclosure, role, and relationship remain source-specific.
- Adopting DisclosureSource evidence
TNFD sector guidance
- Publisher
- Taskforce on Nature-related Financial Disclosures
- Edition
- Final English sector guidance collection through August 2026 (17 documents)
- Requirement
- Not Specified
- Relationship
- Defines Disclosure
- Mapping outcome
- Direct Evidence
- Source locator
- TNFD Oil and Gas sector guidance, Table 13, Response / Dependency, impact, risk and opportunity management: Changes to nature (dependency and impact): mitigation hierarchy steps, OG.A23.0, p.70 | Page 70, Table 13, Response / Dependency, impact, risk and opportunity management: Changes to nature (dependency and impact): mitigation hierarchy steps, Metric no. OG.A23.0
- Adopting DisclosureOG.A23.0
TNFD sector guidance
- Publisher
- Taskforce on Nature-related Financial Disclosures
- Edition
- Version 1.0, June 2024
- Requirement
- Recommended
- Relationship
- Maps Source Identity
- Mapping outcome
- Published
- Source locator
- Page 70, Table 13, Response / Dependency, impact, risk and opportunity management: Changes to nature (dependency and impact): mitigation hierarchy steps, Metric no. OG.A23.0
Value structure
Dimensions and units
- Unit
- number — source-defined reporting unit
- Reporting basis
- Reporting period disclosed by the organisation
Unit meaning: Values use number under the disclosed TNFD sector-guidance method, reporting period and boundary.
Table fields and units
- business activity
- Tier 1 process safety events (number)
- Tier 2 process safety events (number)
- total process safety events (number)
Published dimensions
- process safety event tier
- business activity
Calculation method
Formula information
- Status
- Specified
- Formula type
- Count
Formula
For each business activity, report the count of qualifying Tier 1 process safety events and the count of qualifying Tier 2 process safety events during the reporting period.Apply the source-defined TNFD sector-guidance method within the stated reporting boundary. OG.A23.0 is a reportable additional-sector count metric with explicit Tier 1/Tier 2 and business-activity dimensions. It is not the same construct as shortlisted process-safety event rates or multi-field incident profiles because the TNFD specification calls for counts by tier and activity rather than a rate or broader management profile.
Variables
| Symbol | Variable | Definition | Unit |
|---|---|---|---|
N_{t,a} | Process safety event count | Number of qualifying process safety events of tier t occurring in business activity a during the reporting period. | number |
Verified sources
Evidence and status sources
Sustopedia checked each record-specific claim directly against primary publisher material. Labels distinguish current measurement authority from future compatibility and corroborative, legal, edition, or method status context. Corroborative evidence can support a stated limitation but cannot establish the core measurement by itself.
Measurement evidence
- Measurement evidenceChecked 30 August 2026
TNFD additional sector guidance collection
- Publisher
- Taskforce on Nature-related Financial Disclosures
- Edition
- Final English sector guidance collection through August 2026 (17 documents)
- Locator
- TNFD Oil and Gas sector guidance, Table 13, Response / Dependency, impact, risk and opportunity management: Changes to nature (dependency and impact): mitigation hierarchy steps, OG.A23.0, p.70 | Page 70, Table 13, Response / Dependency, impact, risk and opportunity management: Changes to nature (dependency and impact): mitigation hierarchy steps, Metric no. OG.A23.0
Supports: The official TNFD sector guidance supports the identity, boundary and method basis of “Tier 1 and Tier 2 process safety events by business activity”.
Open official source
Use with context
Interpretation boundaries
Method disclosures required
Source-edition basis: TNFD sector guidance, Final English sector guidance collection through August 2026 (17 documents).
- Define the Tier 1 and Tier 2 process safety event criteria used.
- Disclose the business-activity classification applied.
- State the organisational, operational and value-chain boundary used for event inclusion.
- Describe treatment of events spanning multiple business activities and any restatements or corrections.
Record-specific limitations
- The source specifies event tiers and business-activity disaggregation but does not provide a Tier 1 or Tier 2 event-definition standard in the extracted evidence.
- The metric is a count, not an event rate; it must not be substituted with loss-of-primary-containment rates or general process-safety incident-rate profiles.
Interpret this metric with the stated reporting boundary, period convention, value shape, and unit. Results prepared with different boundaries or conventions may not be directly comparable.
Measurement evidence supports the core record-specific claims described above. Corroborative evidence can support limitations, while compatibility and status sources provide their separately labelled context. None of these cards by itself determines an organisation's legal applicability, filing readiness, assurance status, or compliance conclusion.