# Presentation: 307941

## Unplanned Formation and Detonation of Liquid CLO2

**Lessons Learned**
**For**
**ISMS and Oversight Change**
**By**
**Jeff Williams**
** ****Accident Investigation Team Member**

## Cartoon

**An otherwise calm day at Los Alamos National Laboratory**

## Introduction

**EVENT: Detonation of an estimated 68 grams of liquid (ClO****2****). The explosive force was sufficient to destroy the 3,000 psi. rated vessel and produce projectiles with sufficient force to destroy the fume hood**** ****and penetrate a block wall****. ****If the researchers had not noticed a temperature excursion, evacuated and been missed by all projectiles, the explosion could have resulted in serious injury or death.**

## Reaction

**Objective of “Slurpee” was a high quality Hydrate Solid**
**ClO****2 ****is a “Prohibited” DOT Explosive**
**Hydrate form of ClO****2**** is not dangerous**

- H2O

- H2O

- H2O

- H2O

- H2O

- H2O

- ClO2

- Cl2+2NaClO     2ClO2+2NaCl

## Slide 5

## Similar Experimental Setup

## Hood After Event

## Vessel Base / Witness

## Bottom of Hood

## Ceiling Above Hood

**Ceiling Above Hood**

## Clamp Bolt Witness

## Clamp Missile Witness

## Finite Element Analysis

**Finite Element Analysis**

**The analysis estimated the impulse to be ****approximately 1900 psi-ms**** **

## Synopsis of the Event

**Researcher (luckily) observed a rapid temperature excursion in the ClO****2**** reactor**
**Notified co-worker to evacuate**
**Stepped out and cut power to the CL****2 ****gas valve**
**Explosion took place almost instantly**
**Researcher was 4 feet from being decapitated – couldn’t hear for 15 minutes**

## Synopsis Continued

**Detonation of an estimated 68 grams of Liquid ClO****2**** in a Parr Vessel, equivalent to over 30 grams of TNT**
- Destroyed a fume hood, and caused extensive damage to the lab
- Resulted in a potentially lethal dose of pure Cl2 being released on experimenters and un-informed co-located workers

## Safety Management Systems

**ISM processes and Safe Work Practice Procedures were in place**
- The HCP included adequate controls, but were diluted into 62 pages,
- The controls and experimental limits were NOT concisely defined and,
- Were NOT based on an independent, qualified engineering analysis

## Analysis of Events Leading to the Explosion

**Time Line Analysis**
- Clarifies the steps that led this experiment outside the safety envelope
- Highlights the need for CLEAR definition of operational limits and coordination with the FM
**Barrier Analysis**
- Identifies several well intended, but inadequately analyzed safety assumptions

## Direct Cause

**The Direct Cause of the accident was the failure of the researchers to recognize that liquid ClO****2**** could form in the Parr vessel under the changed conditions of the experiment**

## Contributing Causes

**The controls for handling pure chlorine were not appropriate and not properly placed**
**The system instrumentation was inadequate to detect the existence of conditions in the vessel that could lead to condensation of ClO****2**** in to liquid**

## Contributing Causes cont.

**The Parr vessel was not a suitable containment system for this experiment in that there was excessive confinement for a liquid phase explosion**
**The raising of the dip tube above the surface of the water in the vessel allowed ClO****2**** to condense on the inner surface of the vessel and collect at the bottom, forming and explosive volume**

## Root Cause

**The root cause of the accident was the performance of the new experiment utilizing 100% chlorine gas without a risk determination, formal hazard analysis, independent peer review, a revised HCP, and authorization to perform the work.**

## FR Lessons Learned

**Process Level Oversight, **_**not**_** Task Oversight could have predicted and prevented this event**
- At Large NNSA Sites, FR to M&O ratios (1 to 500) do not permit effective task-level oversight for all hazardous operations
- A task-level focus would not have identified the leading indicators or the need to review this low-profile work

## Conclusions

**Balanced oversight requires effective analysis of data across all site operations**
- Process level oversight of management systems (horizontal)
- Complemented by observation of unique & complex tasks, more likely to indicate weaknesses (vertical)
- Maximizes chance of identifying leading indicators
**This oversight approach is greatly enhanced by using:**
- Automated data collection and analysis tools, tailored to specific processes & requirements in the M&O contract
- Planned and deliberate analysis of data by staff, in order to maximize impact of the oversight program.

## In the words of this experimenter...

**“*****Something just didn’t feel right when we started the experiment that morning.....”***
***“******This was ***_***really***_*** dangerous, I could just feel it.......”***