Quantitative calculation of the fatal explosion damage caused by OT attacks

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This post is a quantitative calculation of the fatal damage by an explosion in a hypothetical, but possible, SIS hack followed by an OT attack scenario.

*A safety instrumented system (SIS) takes automated action to keep a plant in a safe state, or to put it into a safe state, when abnormal conditions are present. The SIS protects against various process hazards including fire, explosion, gas leak, etc.,  in especially chemical plants. But we all know from the last Triton attack that this SIS can also be hacked.(Triton Attack: https://trecto.blogspot.com/2025/03/ot-attack-report-triton-most-murderous.html)


Worst-Case Explosion Scenario in a Chemical Plant Due to SIS Failure

1. Scenario Overview
  • Plant Type: Chemical Processing Plant
  • SIS System: Prevent overpressure and overheating in high-risk chemical storage and reaction vessels
  • Failure Mode: SIS fails to detect abnormal pressure/temperature rise and does not activate emergency shutdown or pressure relief systems
  • Most Dangerous Chemical: Ethylene Oxide (C₂H₄O)
    • Highly explosive when heated and under pressure
    • Toxic, carcinogenic, and extremely flammable
    • Commonly used in sterilization, plastic production, and chemical synthesis

2. Explosion Conditions

ParameterValue
ChemicalEthylene Oxide (C₂H₄O)
Storage Tank TypePressurized Stainless-Steel Spherical Tank
Normal Pressure1.7MPa (250psi)
Normal Temperature10°C (50°F)
Critical Pressure7.2MPa (1,044psi)
Critical Temperature195°C (383°F)
SIS Failure EffectOverheating leads to rapid pressure buildup
Explosion TriggerTemperature exceeds 195°C, causing BLEVE*
Estimated TNT Equivalent30,000kg of TNT

*BLEVE: Boiling Liquid Expanding Vapor Explosion

3. Consequences Analysis Using the Worst-Case Explosion Model

To quantify the impact, we use TNT Equivalent Explosion Energy Calculation:

Eexplosion = Methylene oxide × Heat of Combustion × Efficiency Factor   

  • kg (approx. tank capacity)
  • Heat of Combustion of Ethylene Oxide: 21.1 MJ/kg
  • Efficiency Factor(η) for vapor cloud explosion: 0.1
    • Eexplosion​ = 50,000 × 21.1 × 0.1 = 105,500MJ
  • TNT Energy Equivalent: 4.184 MJ/kg
  • TNT Equivalent:
    • 4.184/105,500​ ≈ 25,215kg of TNT

Thus, the explosion would be roughly equivalent to 25,000 kg of TNT, capable of leveling the surrounding plant area.

4. Impact Assessment

Impact TypeDetails
Human Casualties
  • Immediate deaths: 100–500+ (workers and nearby civilians)
  • Severe injuries: 1,000+ (burns, blast injuries, toxic inhalation)
Environmental Damage
  • Toxic release of Ethylene Oxide causes groundwater contamination
  • Airborne pollutants lead to respiratory diseases
  • Soil contamination leads to long-term ecosystem damage
Financial Losses
  • Direct damage to plant: $500M - $1B
  • Fines and lawsuits: $2B+
  • Supply chain disruption: $500M+
Corporate Reputation
  • Stock value drop: 30-50%
  • Loss of market trust and long-term business partnerships

5. Formula-Based Total Damage Estimation

A general formula for assessing total impact:

Dtotal​ = (Chuman ​+ Cenvironment ​+ Cfinancial ​+ Creputation​)

Using rough estimates:
  • Chuman = 500 × 5M + 1,000 × 500K = 3B USD
  • Cenvironment = 1B USD
  • Cfinancial = 3B USD
  • Creputation = 2B USD

Dtotal ​= 3B + 1B + 3B + 2B = 9B USD


6. Future Prevention & Mitigation

  • Redundant SIS with independent backups
  • Real-time pressure & temperature monitoring
  • Automated emergency relief valves
  • Regular SIS integrity testing
  • OT cybersecurity protection

Conclusion: An OT incident can cause enough damage to put a company out of business. "This is why OT security is so desperately needed"


#CPS #OT #XIoT #IoT #IIoT #IoMT #CPSSecurity #OTSecurity #IoTSecurity #CPS보안 #OT보안 #IoT보안

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