Eugene,

Thanks for the graphic Lessons Learned.

My UCLA colleague and expert in boron chemistry, Professor Alex Spokoyny, says:

"Pentaborane is known to be very toxic (it's super volatile and non-polar and rapidly absorbs through skin) and everyone in the boron community stays away from that chemistry. There is an entire book published on the project ZIP:

https://www.amazon.com/Green-Flame-Andrew-Dequasie-ebook/dp/B00C9Q06YS "

Amazon says:

"Non-fiction account of a classified government project to make high energy fuels based on boron. These materials were toxic, explosive, and spontaneously combustible. There was no OSHA or EPA in the 1950s when this project was active, so it proceeded rapidly right up to its cancellation in 1959."

Craig

Craig A. Merlic

Eugene,

Thanks for the wealth of information on this! I immediately checked our inventory and thankfully we don't have any pentaborane on campus, but I was wondering, how long does the diborane degradation process you mentioned take? We have a few cylinders of diborane on campus and I'm now wondering how imminent a concern this might be.

Sincerely,

Jack Reidy (he/him)

Research Safety Specialist, Assistant Chemical Hygiene Officer

Environmental Health & Safety

Stanford University

484 Oak Road, Stanford, CA, 94305

Tel: (650) 497-7614

Some thoughts and concern. I would exercise extreme caution

The US government had significant interest in the Borane fuels as they have a high impulse/lb. Research started in the late 1940's with three companies involved. They had numerous serious exposures and fatal accidents in 1he 1950's. One company was located in Malta NY next to a GE Rocket Test site. In 1955 they attempted to clean a pentaborane reactor with carbon tetrachloride not realizing it forms a shock sensitive compound. The explosion killed 2 workers and injured others. It destroyed the building. The company packed up and moved to Buffalo. The program to use pentaborane as a fuel was a failure for the B-70 Valkie and the XB 71 Blackbird. To reach Mach 8 they burned pentaborane as a ram jet, Each engine burned 20 tons/hr. Since companies could make only 5 tons per day, it consumed 16 days of production in an hour. In addition the Boron Oxide was abrasive, damaging the engines.

The government in the 1960's then decided to give pentaborane to Universities and Research Labs around the world to see if other uses could be developed. These cylinders have the Best Warning Label I have seen

"Be Damned Sure You Know What You Are Doing Before  You Open this Tank. Read All of the Instructions"!!!!

Depending on storage conditions the boron compounds decompose into the higher boranes. This is why gas suppliers store diborane in a freezer.

Diborane decomposes forming primarily pentaborane. Pentaborane then decomposes finally to decaborane a solid. Penta and decaborane require different chemical methods of treatment. When I was a young Engineer at Matheson I had a project to develop an effective cleaning method for cylinders of diborane that had accumulated penta and deca over time. Some of the treatments can be extremely violent. All of the gas companies have had cylinders rupture. As a result there is a CGA Safety Alert on this problem. All of the gas suppliers now use waste disposal companies such as IES, SET Environmental or Clean Harbors to clean the cylinders. If you contact me I can give you contact into.

Not only is the disposal reaction violent, pentaborane is a severe dermal toxin. A customer employee was cleaning diborane cylinders and when he removed his gloves he accidentally touch the outside. A few hours later half his face was paralyzed. He was treated and recovered. A more severe case was the following.

The first incident resulting from the decommissioning of borane cylinders was reported on February 25, 1982 in Hanover County, Virginia. Twenty one cylinders had been removed from a construction site for decomissioning and one of the workers opened a cylinder to see if it was empty. His bare hand was splashed with pentaborane. Within 4 minutes the worker went into convulsions. In another 4 minutes he slid into a coma. He died 8 days later from acute liver, kidney and brain damage.

A second worker who rushed to aid the first worker, inhaled vapors of pertaborane. He experienced convulsions on the way to the hospital and went into full cardiac arrest at the hospital. Although he survived, he was a quadriplegic and had severe brain damage. A third worker was also exposed at the site; he experienced seizures on the way to the hospital but was later released with no apparent physical problems.

During the incident, 15 other people were exposed and needed treatment. Ten of the people did not experience the symptoms until the next day. Two bystanders and an environmental protection worker were among the injured

By 1998 there had been a number of severe incidents with pentaborane so the EPA Pentaborane Task Force was formed at Environmental Protection Agency National Risk Management Research Laboratory in Cincinnati. They were tasked to find and dispose of any pentaborane cylinders in the US. I am surprised you had not been contacted. In 2003 a customer dropped off a batch of cylinders at our UK facility, 2 happen to be pentaborane. I arranged for one of the 3 disposal companies to travel to the UK to dispose of them. Extremely expensive as you can imagine. They contacted the US Navy and they came and took them away

Disposal is not a task you should perform because of the extreme danger. Even the Military failed when they blew up pentaborane cylinders with shaped charges. It did not get rid of the solid decaborane. One of the disposal companies was contracted to finish the job. As this one time disposal will be extremely expensive you should contact all three companies for a price. I don't believe Veolia does the actual disposal. They use one of the three. Contact me and I can help you through this process

Eugene Ngai

Chemically Speaking LLC

www.chemicallyspeakingllc.com

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