Fatal Gas Well Blowout and Explosion
Wendland 1H Well Fatal Explosion
Chesapeake Operating, LLC / Chesapeake Energy
📍 Burleson County, TX
Incident: January 29, 2020  •  CSB Report: December 26, 2023
3
Fatalities
4
CSB Recommendations
📋 Incident Summary

On January 29, 2020, an explosion fatally injured three contractors at the Wendland 1H natural gas well in Burleson County, Texas, operated by Chesapeake Energy. A workover crew was performing well servicing on the well. Workover operations involve removing and replacing downhole equipment in a temporarily shut-in well. The crew opened the well without establishing adequate well control barriers -- the well flowed, the gas release ignited, and three workers were killed.

The CSB found that the workover planning did not include a review of the well's history. A well history review would have revealed that the Wendland well had previously experienced unexpected gas flow during similar operations -- indicating the well retained reservoir pressure and could not be assumed depleted. Without that review, the crew treated the well as low-risk and did not establish secondary well control barriers. Industry standards require two independent barriers during workover operations.

The CSB's final report, released December 26, 2023, issued four recommendations. One -- requiring Chesapeake to incorporate well history review into workover planning -- has been closed as completed. Three remain open: two to OSHA calling for a new PSM-equivalent standard for oil and gas well operations and removal of the current well-servicing exemption from the Control of Hazardous Energy standard; and one to API to update API RP 59.

🔎 Key Findings
Finding 1
Well History Not Reviewed Before Workover
Workover planning for the Wendland 1H well did not include a review of well history. Prior documented flow events would have indicated the well retained reservoir pressure and was not safe for unbarriered workover.
Finding 2
Inadequate Well Control Barriers
Industry practice and API RP 59 require two independent well control barriers during workover. The crew opened the well without establishing secondary barriers, leaving no backup if the primary barrier failed.
Finding 3
Stabbing Valves Not Adequate Well Control Barriers
A stabbing valve was used as a well control device. CSB findings and API guidance both confirm that stabbing valves are not adequate well control barriers for workover operations.
Finding 4
Oil and Gas Wells Exempt from Energy Control Standard
OSHA's Control of Hazardous Energy standard (29 CFR 1910.147) explicitly exempts oil and gas drilling and well servicing, leaving workover workers without formal energy isolation protections.
Finding 5
No PSM Equivalent for Oil and Gas Well Operations
OSHA's PSM standard does not apply to oil and gas production and workover operations. No requirement existed for hazard analysis, written workover procedures, or management of change at this well.
Finding 6
Three Fatalities -- All Preventable
Every contributing factor at Wendland -- well history review, dual barriers, energy isolation -- was already required or recommended in existing industry standards. The knowledge existed. The application was absent.
🔍 Root Causes
1
Well History Not Incorporated in Planning
The workover plan did not incorporate a review of documented well history, including prior flow events that demonstrated retained reservoir pressure. Without this review, the crew operated under an inaccurate assumption about the well's hazard state.
2
Single Well Control Barrier
Opening the well with a single barrier violated API RP 59 requirements for two independent barriers during workover. A single barrier failure with no backup is a direct path to an uncontrolled blowout.
3
Regulatory Gap in Oil and Gas Well Safety
No OSHA standard requiring hazard analysis, written procedures, or management of change applied to this workover operation -- reflecting an industry-wide gap in regulatory worker protection for well servicing.
4
Industry Standard Not Applied at the Worksite
API RP 59 contained guidance that could have prevented these fatalities. That guidance was not incorporated into Chesapeake's workover policies and therefore not applied at the well site.
☑ CSB Recommendations
→ Chesapeake Operating, LLC
Develop or revise workover planning policies to incorporate API RP 59 guidance requiring well history review -- including all prior flow events and pressure anomalies -- before any workover operation. [STATUS: CLOSED -- Acceptable Action]
→ American Petroleum Institute (API)
Publish workover-specific well control guidance in API RP 59, including: well control methods for underpressured reservoirs; confirmation that stabbing valves are not adequate well control barriers; and a requirement that every well be assumed capable of flowing with two barriers established before opening.
→ Occupational Safety and Health Administration (OSHA)
Remove the exemption for oil and gas drilling and well servicing from the Control of Hazardous Energy standard (29 CFR 1910.147) and expand its coverage to oil and gas production and workover operations.
→ Occupational Safety and Health Administration (OSHA)
Promulgate a new standard for onshore oil and gas well operations with prescriptive energy isolation requirements and a performance-based safety management framework addressing well control barriers, written procedures, hazard analysis, employee participation, and management of change.
💡 Lessons Learned
⚠ Every well should be assumed capable of flowing until two independent well control barriers confirm otherwise. 'This well should be depleted' is not a well control barrier.
⚠ Well history is process safety information for oil and gas wells. Before any workover, the well's documented history -- including all prior flow events and pressure anomalies -- must be reviewed and incorporated in the well control plan.
⚠ The regulatory gap that exempts oil and gas well servicing from OSHA's Control of Hazardous Energy standard leaves workers unprotected. Companies cannot wait for regulation -- they must apply equivalent energy control principles voluntarily.
⚠ Two independent well control barriers are required because any single barrier can fail. A stabbing valve is not a secondary barrier. Industry standards have stated this clearly for decades.
⚠ Three contractors died at Wendland because well control practices that existed in API RP 59 were not applied to this workover. The knowledge was available. The application was absent.
PSM Elements: PSI · SOP · TRN · MOC
🔨 Safety Meeting Toolbox Talk
Topic: Well Control, Well History, and Energy Isolation in Oil and Gas Operations
💬Before any workover or well servicing operation, is a formal well history review required -- specifically including all prior flow events, pressure anomalies, and any prior blowout control events?
💬What are the two independent well control barriers required by API RP 59 for workover operations? Does our workover plan require verification that both are established before opening the well?
💬Does our company's well servicing policy treat stabbing valves as adequate well control barriers? If yes -- that policy is inconsistent with API RP 59 and CSB findings.
💬How do we apply Control of Hazardous Energy principles -- equivalent to OSHA lockout/tagout -- to oil and gas well servicing, even though those operations are currently exempt from 29 CFR 1910.147?
💬What would happen if the well we are working on today unexpectedly flowed? Who is the well control authority at our worksite, and is there a documented emergency response for an uncontrolled flow event?
💬When did our company last review workover procedures against current API RP 59 guidance? Are specific well control methods for underpressured reservoirs addressed in our SOPs?
✎ Team Action Items
✓Review the well history file for the next scheduled workover -- confirm it includes all documented flow events and pressure anomalies, and that the well plan addresses any anomalies found
✓Review your workover procedure and verify it requires two independent well control barriers to be documented and in place before any tubing or completion component is opened
✓Confirm your company policy on stabbing valves -- verify they are not listed as adequate primary or secondary well control barriers in any current workover procedure
✓Review your worksite emergency response plan for an uncontrolled flow event -- confirm all crew members know the immediate response, muster location, and who holds well control authority
🔗 PSM Failures Behind This Incident

This incident traced to breakdowns across 4 PSM elements (PSI · SOP · TRN · MOC). Each represents a documented gap that process safety documentation and consulting can close before a similar event occurs at your facility.

Process Safety Information (PSI)
Accurate, complete Process Safety Information is the foundation every other PSM element depends on. When PSI is missing or wrong — chemistry data, equipment specs, P&IDs — the entire hazard analysis is built on a flawed base.
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Operating Procedures (SOPs)
Operators cannot reliably hold safe operating limits without clear, current, enforced procedures. Deviation from acceptable operating conditions — a root cause here — is a direct consequence of SOP failure.
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Training & Operator Competency
Workers must understand process hazards — not just the steps on the page. Training records, refresher frequency, and verified competency are all OSHA PSM requirements that gaps here violated.
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Management of Change (MOC)
Changes to equipment, chemistry, operating limits, or procedures that bypass formal review create new hazard pathways your PHA never evaluated. MOC failures open the door to incidents like this one.
Supporting documents in our library →
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