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Previous by Date: Subject: Re: [DCHAS-L] Chemical Safety headlines (19 articles) Date: Saturday, August 22, 2020 at 5:32:19 PM Author: Eugene Ngai <eugene_ngai**At_Symbol_Here**COMCAST.NET> |
Next by Date: Subject: Re: [DCHAS-L] EXTERNAL EMAIL: Re: [DCHAS-L] Chemical Safety headlines (19 articles) Date: Sun, 23 Aug 2020 11:16:18 +0000 Author: "Wright, Mike" |
Eugene,
No apology for the lengthy reply is necessary. Frankly, I found it a good summary of the global situational aspects responders perform an initial assessment on while responding. I can't agree more with how they assess at the time of initial response v. the time required for a good root cause analysis. The first is reactionary based upon the best evidence available to responders, while a good root cause analysis is performed by those of us specializing in safety assessments - reviewing all aspects of the accidents causes. A night and day difference, that must be acknowledged in any further discussions. The perspective the decisions are made are critical, and so should the analysis of first responder versus accident investigation be. I thought your response was exactly on point.
Well done,
BruceV
-----Original Message----- The Fire Dept was correct to call it an explosion. The definition of an explosion is a violent expansion in which energy is transmitted outward as a shock wave. While many believe that this can only be due to a chemical reaction, a gas cylinder that is being overpressurized with gas will rupture suddenly. The high pressure gas released will form a shock wave that we hear as a detonation. A balloon pop is an example of this. That is what happened with the CO2. The sudden high pressure release blew apart the ground and concrete. -----Original Message----- As to this tidbit: An explosion beneath a fire equipment company in Ashland that forced multiple people to evacuate their homes Tuesday evening was caused by a carbon dioxide leak, officials said. Authorities responded around 6:20 p.m. to ‰??numerous 9-1-1 calls‰?? about a large explosion at Kidde Fenwal, a business on Main Street, according to the town‰??s police department. ‰??Firefighters immediately checked for injured workers, began searches of adjacent buildings and conducted air monitoring to avoid a secondary explosion. A Tier-1 Hazardous Materials incident was declared,‰?? the department said in a Facebook post. Carbon dioxide was leaking from a ruptured supply line at the company, which prompted the blast and subsequent hazmat response, the Ashland Fire Department said.> Y'all know my bias about the willy-nilly use of the term "explosion." This really doesn't make any sense to me at all. Was the risk of additional catastrophic failure of the compressed gas system the reason for the level of response? Was there a risk to other compressed gas systems which are hazardous (carbon dioxide is a simple asphyxiant)? Other issues? Debbie Debbie M. Decker, ACS Fellow --- --- ---
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From: ACS Division of Chemical Health and Safety
Sent: Saturday, August 22, 2020 5:32 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Chemical Safety headlines (19 articles)
All public responders (Police, Fire, EMS, HazMat) are trained to perform a ‰??Size Up‰?? as they are approaching the scene and to continue this assessment while they are on scene. This assessment will dictate their actions. They do this for a fire, motor vehicle accident, chemical spill, industry accident, etc.
Their primary concern is to remove and treat the injured, can the public be affected,? what happens if we do nothing, will it get worse?
Private responders are not trained or have the discipline to do this. For company responders who work with the products daily and have an extremely limited scope it is almost always immediately clear what they must do in an incident.
A public HazMat team on the other hand doesn‰??t have a well defined scope of what they must respond to. What they must deal with is considerable and complex in scope. The major areas are Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE).
Public responder universe
1. Different modes of transport, rail, truck, ship, air 2. Packages ‰?? small vial to railcars 3. Chemicals ‰?? over 5,000 hazardous chemicals are in common use 4. Biological 5. Radioactivity 6. Explosives 7. Weapon of Mass Destruction They can never be an expert on all of these. As a result, first responders are trained to take a disciplined and methodical approach to any emergency for safety.
They have no choice but to respond and deal with any situation which often is chaotic. It is easy after the fact to second guess since all the facts are now known..
Think about what the Battalion Chief was initially faced with
1. There was an explosion due to unknown causes, can it happen again? The supplier is on the way but it will probably be at least an hour for them to arrive. I would want my HazMat team there at the very least to provide technical and equipment support. A Tier 1 response is the lowest level response. You can always send them away, You lose valuable time if all of a sudden they are needed.
2. A geyser of liquid CO2 is shooting into the air. Can it come back to ground level and asphyxiate someone? As shown in the Sept 2016 DHS Cl2 Jack Rabbit III terrorism release testing at Dugway, 4 tons of gaseous/liquid Cl2 was released through a 6‰?? dia hole on top of a 20 ton tank in minutes hundreds of feet up into the air. Since Cl2 is 2.5 times heavier than air you can actually see in the video the plume come back onto the ground. Gaseous CO2 is 1.52 times heavier than air in addition since it was refrigerated the gas is even heavier. CO2 is colorless and odorless there will be no warning if it happens.
3. The BC knows from recent fatal accidents at McDonalds and other fast food locations that CO2 is not easily detected based on the many presentations at HazMat Conference. Many oxygen sensors are rendered useless due to the CO2 neutralizing the electrolyte, so how do you assess the area?
4. DOT distributes free copies of the North American Emergency Response Guidebook to every public agency in the US. It is intended to provide initial guidance for incidents involving chemicals for the first 30 minutes of a response. They are expected to use the information until better information is available. The NAERG for refrigerated CO2 (Guide 120) states that a minimum of 100 meters should be evacuated. These are updated every 4 years. Private HazMat teams are expected to be knowledgeable on the NAERG.
The Battalion Chief is a trained Firefighter and Rescue person, He/She typically has very little knowledge of chemicals but timely decisions must be made.
One of the parttime activities that I have enjoyed over the last 30 years has been teaching Compressed Gas HazMat around the world. Korea, UK, Phoenix, New York, San Jose, Singapore, etc. As a state, Massachusetts has one of the best HazMat systems. In my opinion the Ashland FD did the right thing.
Sorry for my lengthy reply.
Eugene Ngai
Chemically Speaking LLC
www.chemicallyspeakingllc.com
From: ACS Division of Chemical Health and Safety
Sent: Friday, August 21, 2020 2:56 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Chemical Safety headlines (19 articles)
Tags: us_MA, industrial, explosion, response, carbon_dioxide
Division Councilor
Programming Co-Chair
Retired Chemistry Dept. Safety Manager
dmdecker**At_Symbol_Here**ucdavis.edu
(916)616-7548
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For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas
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Follow us on Twitter **At_Symbol_Here**acsdchas