Company Information

Chemically Speaking LLC is a specialty gas consulting company that can provide safety, environmental and emergency response support to users, transporters, distributors, waste disposers or manufacturers of specialty and industrial gases used in the chemical, medical, electronics and automotive industries. Chemically Speaking can also provide safety and emergency response training. Expert witness or incident investigation.


Aug 22, 2021

To All

I have received many anxious and sometimes demanding inquiries as to when my blog will be ready and posted. I can assure you that it has been a productive 3 months so far. Have written over 300 pages of lessons learned, gas history, emergency response techniques, etc. It has been an interesting exercise to go back through my files and finding information that I forgot about as well as being able to chat with industry old timers who added to my understanding of what happened in some incidents. Many old timers are glad that I’m making the effort to capture these for history otherwise their legacy knowledge would be lost forever. I’m sad however that other old timers that I have known and reached out to haven’t responded to my requests, so I know there will be many learnings I will miss.

Based on what I have written so far, I am excited that I will be covering ground that on one has done before.

For example, some of the completed summaries

1.       History of the Development of the Restrictive Flow Orifice (RFO)

2.       Explosive Gas Mixture Incidents each are over 20 pages with many historical pictures or a summary of over 40 key incidents.

Each contain numerous references that I must review again for accuracy.

3.       Others like Development of Pneumatic Cylinder Valves or The Development of the DISS Connection while shorter in length are taking time to organize and edit with credible information in order to present  an accurate and coherent summary.

4.       How many know that the reduction in germane fill density after the cylinder explosion in 1984 has prevented at least 3 catastrophic cylinder failures in recent years? yet the DOT and the UN in 2004 unaware of this history proposed an increase the fill density! I reminded them of the history and the industry Best Practice in a letter that also summarized the fatal accident with nitric oxide that reduced the fill pressure.

5.       The India silane explosion that was reported to me when I was in India in 2008 involved a release into a 2 cylinder gas cabinet, yet it was so powerful that it decapitated the operator’s  head and propeledl his body into a brick wall damaging it. The explosion completely flattened the metal gas cabinet against the wall. It was built to the US International Fire Code Standards by a US company.

6.       Prepared a summary of over 300 silane incidents. An unbelievable event was finding the gas supplier operating a silane distribution center from the basement of a motel! Even more unbelievable was the 3 instances of companies attempting to remove the cylinder valve while there was still silane in the cylinder!

In the HazMat community there have been a number of urban legends that are followed that are not based on fact.

1.       Is the LOx 30 minute rule safe?

2.       What is the 1/7 rule for acetylene? What does it mean in a response? Is it unsafe to lift an acetylene cylinder vertical?

Are these effective. Testing is underway to determine this

As these are meant to capture important safety issues/learnings, it is critical that they be as accurate as possible. I have made every attempt to verify that the key information has been documented in an investigation report, journal article or some other public document. All have been sanitized to not reveal the company or location.

I also have been fortunate to have another gas industry old timer, Ed Van Schoick review and comment on my summaries. He has 6 more months of experience in the compressed gas industry than I do! He has been invaluable in providing additional information, comments or insights, making the summaries much more powerful.

Please bear with me as I don’t want to put the blog online as I’m only 40% done. If I do it now, I’m afraid I’ll be swamped with questions or comments that would take me away from finishing. There is also a question about copyright and acknowledgement with the blog. Can someone simply download everything and publish it with them as the author? That has happened to me before.

I have also thought about what can happen to all this work if something happens to me before it goes online. As insurance, all of the files are in a Dropbox file that my oldest daughter can access. She has been instructed to publish all that I have marked done and to have the works in progress be reviewed by Ed for completeness before posting.

Jan 16, 2021

Last week there was a serious incident involving Tetramethylammonium Hydroxide (TMAH), a chemical that is widely used in the Semiconductor Fab. It is not known what the final outcome is of the 6 individuals that were exposed, 2 were serious. In many large Fabs TMAH is piped throughout the facility at various concentrations.

Of all the reactive/pyrophoric or toxic chemicals used in the Fab, TMAH is one of the top 5 that I have a concern with as there appears to be no effective medical treatment protocol. I spoke to Dr. Wu at my 2008 training class on Trichlorosilane Safety and ER in Taiwan.  As a consultant to the Taiwan Poison Control Center he has been involved in TMAH incidents, 3 of which were fatal. He spoke of one in which a worker was alone and was splashed with a 25% solution. He immediately went to the safety shower. He was found 15 minutes later barely conscious. Prior to arrival at the hospital he went into cardiac arrest. He was resuscitated but he slipped into a coma and died 8 days later.

High concentration (25%) exposure of 7% of the body is fatal! Even lower concentration can also be

Park et al., J Occup Health, 2013

39 yr old male splashed 8.75% TMAH on his hands, arms and legs

12% body surface area affected

Continued working and went to the shower room 25 mins after the spill

He was found dead outside the shower ~60 mins later

Second degree burns on skin

IBM Medical and Safety professionals conducted a detailed review of incidents as well a sponsored extensive animal dermal exposure testing. They presented their findings at the 2011 Semiconductor Environmental Safety and Health Association (SESHA) Conference with an update in 2018. I have summarized the LG Display incident as well as the 2011 IBM presentation to educate those that have limited knowledge of TMAH.  The presentation was updated in 2018. It can be downloaded for free to SESHA members. Membership is free.

My summary can be found in Files


Aug 2020

 I had the pleasure of collaborating with my daughter Courtney (PhD in Chemistry Education) on a peer reviewed article for the ACS Journal of Chemistry Education "Compressed Gas Safety At The University". She is a gifted writer who was able to take my Engineering mumbo jumbo and put them into coherent and meaningful sentences. It was interesting to work with a child who is now my peer.

J. Chem. Educ. 2021, 98, 1, 57–67 July 22, 2020

Feb 2020

Happy to report that I just received my 6th US patent. No. 10550002 “Method for treatment of hexachlorodisilane and hydrolyzed product”, Feb 4, 2020

Feb 9, 2020

I am 67 years old and in the last five years I have asked myself if I have used my knowledge to make a difference in the world. As a result, one of the key goals I have set for myself is to leave behind to this and future generations things that I have learned in the many years of working in the unique world of specialty compressed gases. I try to do this by continuing to mentor engineers and scientist in Taiwan, Korea, China and Singapore, writing safety articles, teaching safety and participating in industry/fire standards development. I have been happy donating 25% of my time and money by participating in NFPA, CGA, ISO and SESHA committees.

I would hate to think that someone was injured or died because they were not aware of lessons we learned in the last 40+ years. One sad fact is that many professionals with my background have been early retired and their knowledge and expertise is lost forever. When I started as a Chemical Engineer many years ago, there was an old timer down the hallway that would listen to my interesting ideas, chuckle and then proceed to tell me why he wouldn’t do what I proposed. That support is no longer available, where does a young professional go for guidance? An extreme example of this knowledge loss was when the UN Transportation of Dangerous Goods (TDG) in 2005 was updating the cylinder fill limits for compressed gases. They were not aware of the incidents involving germane (1984), stibine and nitric oxide (1968). These incidents caused a fatality or significant damage. As a result the gas industry lowered the fill limits of these cylinders so that they would contain the sudden overpressure if a reaction occurred. This reduction has saved the industry from at least 5 cylinder ruptures that I am aware of. Ignorant of this fact they were going to increase the fill limits based on other criteria that made sense.


I have been very fortunate during my 40+ years in the compressed gas industry to have learned from some of the best in first generation, Al Mossman, President of Matheson (Author of Matheson Gas Data Book, Compressed Gas Medical Treatment) Herb Gill, founder of Precision Gas Products, Bill Kalaskie, Superior Valve, etc. During these years I was exposed to a wide assortment of specialty gases throughout their lifecycle, R&D, manufacturing, purification, QA, emergency response, waste disposal, all with handson experience. I have been making the metal hydride gases such as arsine, diborane, germane and phosphine since 1972 at locations around the world. I was also lucky to have had the staff, company support and resources to experiment with many of the exotic gases to better understand their properties and release behavior these include chlorine trifluoride, silane, trimethylaluminum, hydrogen selenide and fluorine. Very few engineers actual get to build or operate systems. I have been a principal in the investigation of numerous compressed gas incidents including the largest release of arsine (65 lbs) in 2001 and the U of Hawaii explosion 2016. I have been given a “gift” in life. People actually pay me to do things I want to do plus pay my expenses and research. Does this get any better?

I have also on a part time basis, teaching and advising public and private HazMat teams around the world on compressed gas emergency response since 1990. This proved to be of value in the U of Hawaii investigation as I had trained HazMat 1, Honolulu FD exactly a year before. They made entry into the lab after the explosion and were able to share with us their initial assessments, pictures and reports. I can reach out to many HazMat teams in the US and get an immediate answer to a problem.

 Jan 21, 2019

Chemically Speaking LLC is celebrating 10 Years on Feb 1, 2019!  A milestone! I have had many compliments on the name but I can’t take credit for this, Courtney said Dad you can’t have a boring name how about this? It fits! I am now 67 and could easily retire but yet here I am with a full schedule!

During these 10 years I have been having great fun! I have never had to advertise, yet people find me. 2019 is already booked through April with lots of interesting projects on some cutting edge research or University Research projects that will change our lives. Of course. I’m still looking at blowing some things up in the interest of science! Hope to recreate events leading up to 4 fatal accidents with organometallic materials.

Am also looking at buying a small technology company with many patents for a client. What’s nice is I’m at the point where I can tell someone to stuff it. Did that twice in 2018! Felt good!

Travelled just under 2 million miles to exciting places around the world. I continue to do research on chemical safety and plan to do more in 2019. It’s nice to have a sense of purpose in life. Put together and chaired a seminar in April that had 70+ people worldwide pay $450 to attend on a highly reactive chemical that killed 5 in 2014 and destroyed a manufacturing plant in the US. Will do another seminar this year based on another year of research paid for by 2 customers.

One patent, 5 peer reviewed articles plus 6 non peer reviewed articles. Convinced 12 companies to chip in $500,000 of money and equipment to do 4 days of testing in New Mexico. Got them to fund some more testing a year later. Trained or presented to over 8,000 Firefighters or University employees.

Investigated 5 serious explosions and determined root causes of these during this time. In many the damage was so severe that it was a challenge to determine what might have happened.

There is nothing more rewarding than to pass on or discover new items that can help to protect people. I see many students from classes 10+ years ago that are still very eager to learn. Donate 20% of my time plus $20,000 every year to train this generation.

Getting paid a lot of money to do all this is icing on top! I would do most of this for nothing because its so interesting.

I am a very lucky guy!

Oct 20, 2018

Great news! After a year of ground breaking research on the shock sensitive gel formed by Hexachlorodislane, Prof Chen and I have been issued a Taiwan Patent "Process for Treatment of Hexachlorodislane and Hydrolzyed Product", Taiwan Patent I634939 Sept 11, 2018. This gel was involved in a fatal accident in Japan that killed 5 and injured 13. No one knows how to handle it.
Since this was applied for 7 months ago additional research has uncovered another new and novel process patent that will be applied for. To continue to get paid to do ground breaking research at Medicare age is rewarding as well as helps my mind from drifting into Dementia!
I know of others that have had serious explosions or problems with these gels. It has been exciting to be able to conduct detailed research to uncover effective methods to neutralize these reactive gels. Unfortunately we have found that there is not one method that is effective. Hope to present the results of this at another SESHA PDC in April 2019

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Sept 2018

Accidental Reaction of Metal Alkyls (Organometallic compounds) with Moisture or Air Causing a Cylinder to Rupture

Metal Alkyls (Organometallic) are finding increasing use in the Silicon Semiconductor Fabrication Industries. The most commonly used are:

Trimethylgallium (TMG)

Trimethylaluminum (TMA)

Trimethylindium (TMI)

Diethylzinc (DEZ)

The III-V device manufacturers typically dispense these from a cylinder configured to function as a bubbler (A carrier gas is bubbled through the liquid/solid to be saturated with the vapor). To maintain a precise concentration the cylinders are immersed in a heated or chilled water bath (glycol). These are located within the tool (MOCVD) and are maintained under positive pressure. A leak if it were to occur it would be outward causing a fire.

The silicon device manufacturers on the other hand dispense Trimethylaluminum by pulling a vacuum on the vapor space of the canister in the ALD process (Atomic Layer Deposition). Due to the larger volumes used, a small host container is located close to the tool in the cleanroom. This is constantly filled by larger bulk supply and process containers located in the subfab, these are pressurized to fill the canister. Diethylzinc is used to grow a transparent conductive layer for a thin film photovoltaic cell. The use of Metal Alkyls is forecasted to increase dramatically for all uses.

Pyrophoricity (spontaneous ignition) and fire is probably the most well-known hazard characteristic of these key organometallic compounds. A fire is commonly encountered during accidental release of Metal Alkyls into air. Most current safety precautions for handling these materials are associated with the pyrophoricity.

Violent reaction with liquid water is also a well-known problem. The hydrolysis reaction may generate sufficient heat to trigger a self sustained decomposition reaction.

Can the ingress of air or water in the ALD process trigger a self sustaining decomposition reaction that ruptures the container? These Metal Alkyls are also thermally unstable. Heat can trigger a decomposition reaction. Imagine a spill around a container that is on fire water cannot be used to cool the container or put out the fire.

There have been 5 known fatalities plus numerous injuries due to these causes that ruptured the container

Known incidents

TMG container explosion after glycol is sucked in (date unknown)

TMI container explosion after air sucked in, Dec 11,1998 (2 injuries)

TMI container explosion after it was heated to decomposition temperature, 2012 (1 injury)

TMI container explosion from moisture from valve, Oct 9, 2013 (1 fatality, 1 injury)

TMA container explosion after air is sucked in, Jan 7, 2016 (4 injuries)

TMI explosion, cause unknown, Feb 16, 2017 (3 injuries)

TMI container explosion after air is sucked in, May 2018 (2 fatalities, 1 injury)

TMI container explosion, cause unknown, Sept 19, 2018 (1 fatality, 3 injuries)


A test program is to better understand what can happen with Trimethylaluminum in a typical ampoule (1 liter) in a worst case incident has been proposed for 2019.

Open valve to suck in air.

Drip 5 cc of water into container.

If any of the tests do not trigger a decomposition reaction, heat container to decomposition temperature


The test program will

Video from 4 angles

High speed video of container rupture

Canister pressure measurement

Temperature measurement

Overpressure sensors in a x-y grid


Test Directors:

Prof. Jenq-Renn Chen, Department of Safety, Health and Environmental Engineering, National First University of Science and Technology, Kaohsiung, Taiwan.

Eugene Ngai, Chemically Speaking LLC, Whitehouse Station, NJ 08889,



Recent publications

  1. Lin, Y. J., Liu, C.H., Chin. M.G., Wang, C. C., Wang, S.H.. Tsai. H.Y.,Chen, J.R., Ngai, E.Y. & Ramachandran R.. “Characterization of Shock Sensitive Deposits from the Hydrolysis of Hexachlorodisilane” 12th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions Kansas City, USA - August 12-17, 2018 
  2. Ngai, E., Chen, J.R , Tsai, H.Y. et al, Unconfined Silane-Air Explosions, 11th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions, Dalian, China, July 24-29, 2016
  3. Ngai, E. Y., Fuhrhop, R., Chen, J. R.*, Chao, J., Bauwens, C. R., Mjelde, C., Miller, G., Sameth, J., Borzio, J., Telgenhoff, M.. Wilson, B., CGA G-13 Large-Scale Silane Release Tests – Part I. Silane Jet Flame Impingement Tests and Thermal Radiation Measurement, Journal of Loss Prevention in the Process Industries, Vol 36, July 2015, pp 478-487
  4. Ngai, E.Y., Fuhrhop, R., Chen, J. R.*, Chao, J., Bauwens, C. R., Mjelde, C., Miller, G., Sameth, J., Borzio, J., Telgenhoff, M. Wilson, B., CGA G-13 Large-Scale Silane Release Tests – Part II. Unconfined Silane-Air Explosion, Journal of Loss Prevention in the Process Industries, Vol 36, July 2015, pp 488-496
  5. Ngai, E., Chen, J.R. , et al, “CGA G-13 Large-Scale Silane Release Tests – Part I. Silane Jet Flame Impingement Tests and Thermal Radiation Measurement”, Tenth International Symposium on Hazards, Prevention, and Mitigation of Industrial Explosions, Bergen, Norway, 10-14 June 2014
  6. Ngai, E., Chen, J.R. , et al,  “CGA G-13 Large-Scale Silane Release Test –Part II. Unconfined Silane-Air Explosions”, Tenth International Symposium on Hazards, Prevention, and Mitigation of Industrial Explosions, Bergen, Norway, 10-14 June 2014
  7. Ngai, E., “Dangerous Gas Mixtures: Avoiding Cylinder Accidents” Specialty Gas Reporter, 2nd Qtr 2014

  8. Ngai, E. “Phosphine, From Swamp Gas to Applications in the Clean Room”, Cryogas International, 2nd Qtr 2014
  9. Ngai, E. Y., Fuhrhop, R., Chen, J. R.*, Chao, J., Bauwens, C. R., Mjelde, C., Miller, G., Sameth, J., Borzio, J., Telgenhoff, M.. Wilson, B., CGA G-13 Large-Scale Silane Release Tests – Part I. Silane Jet Flame Impingement Tests and Thermal Radiation Measurement, Journal of Loss Prevention in the Process Industries,
  10. Ngai, E.Y., Fuhrhop, R., Chen, J. R.*, Chao, J., Bauwens, C. R., Mjelde, C., Miller, G., Sameth, J., Borzio, J., Telgenhoff, M. Wilson, B., CGA G-13 Large-Scale Silane Release Tests – Part II. Unconfined Silane-Air Explosion, Journal of Loss Prevention in the Process Industries (2014),