Inadvertent synthesis of triacetone triperoxide (TATP)
May03

Inadvertent synthesis of triacetone triperoxide (TATP)

Via C&EN’s letters to the editor this week, some 1970s-era safety letters regarding inadvertent synthesis of triacetone triperoxide (TATP): Violent explosion (Feb. 21, 1977, page 5): While making 6-amino-penicillanic acid S-oxide, there was an explosion in our laboratory, at which time one man was injured. The cause of the accident has been found to be trimeric acetone peroxide. For the experiment in question we used 1 mole of 6-APA. It was oxidized according to the instructions published in “Synthesis” 1976, page 264, and precipitated as p-toluene sulfonate in the presence of acetone. 130 grams (0.32 mole) of the product was treated with triethylamine in isopropanol according to the instructions. The precipitate was filtered with suction on a glass sinter, washed with acetone, and air was allowed to flow through the filter cake. When the technician who was performing the experiment took the sinter in his hand and touched the precipitate with a steel spatula, it exploded violently. The technician received severe burns and splinter wounds in his eyes, hands, and body. Two windows were broken and there were holes in the glass of a fume cupboard at 3 m distance. The surface of the work table was spoiled. The explosive substance was found to be trimeric acetone peroxide. It was isolated from the mother liquor, from which it crystallized as large crystals. The melting point of the substance was 97° C. In literature [“Encyclopedia of Explosives and Related Items,” Vol. 1, Basil T. Fedoroff, Picatinny Arsenal, Dover, N.J. (1960)] the melting range is given at 94 to 98.5° C. The infrared spectrum was identified with the aid of a computer, and it was identical with the spectrum in the Sadtler catalog. On the basis of the NMR spectrum it was established to contain only one type of protons, τ = 8.5. The explosion of trimeric acetone peroxide was probably caused by the combined effect of static energy and friction. The static energy accumulated in man can be 30 mJ. We performed different sensitivity tests with the isolated substance. It exploded moist with an 11.5-mJ electric spark. In impact sensitivity tests, it ignited repeatedly with a weight of 2 kg from 10 cm’s height. In friction sensitivity tests, the sample ignited with a weight of 0.5 kg. The ignition sensitivity increased when the substance was dried. Trimeric acetone peroxide was the only explosive compound that we were able to isolate from the mother liquor that was spared. Thus we have every reason to believe that just this substance caused the accident. According to literature, acetone peroxide is easily produced from acetone and hydrogen peroxide catalyzed by an acid. A. Noponen...

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Report on U Hawaii explosion delayed until late May
Apr28

Report on U Hawaii explosion delayed until late May

From the University of Hawaii regarding the March explosion that caused a postdoctoral researcher to lose one of her arms. UH retained the University of California Center for Laboratory Safety to investigate the incident, and that report was expected this week. The independent investigation into the March 16, 2016 explosion in a University of Hawaiʻi at Mānoa laboratory is now expected to be complete in mid to late May. It was initially expected to finish by the end of April. The University of California Center for Laboratory Safety, retained by UH to conduct the investigation, was unable to send materials involved in the explosion for testing until the Hawaiʻi State Occupational Safety and Health Division (HIOSH), the government agency investigating the accident, completed its review of the accident scene. HIOSH released the materials and scene to UH late last week. … In its preliminary investigation, the UC Center for Laboratory Safety, considered a national leader in laboratory safety, determined that the explosion was an isolated incident and not the result of a systemic...

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“We felt the explosion rattle the floor and walls eight floors up…”
Apr26

“We felt the explosion rattle the floor and walls eight floors up…”

We’ve had a lot of comments at C&EN about my story, “Spark from pressure gauge caused University of Hawaii explosion, fire department says.” I thought I’d flag a few of them here: I am a researcher in the same building as the HNEI, although not on the same floor, and not in the same field. We felt the explosion rattle the floor and walls eight floors up – Dr. Ekins-Coward is truly lucky to be alive. The incident has prompted campus-wide laboratory safety re-certification efforts here, particularly with regard to pressurized gas cylinders, whether or not they contain flammable gases. PIs, please take the time to discuss with your lab staff and students proper gas handling – students and staff, if you see red flags, don’t let up until your PI fixes the issue. It really sucks having something like this happen in your University, let alone your own lab building and community. — I can empathize with this researcher…. I work with Hydrogen, CO, and O2 in the lab and did not consider the issue with fires…. I will conduct a SAP review and modify our current working conditions. I teach a safety course and work closely with SAChE but and aware of the LFL and UFL of H2… we as researchers get tunnel vision. I am very sorry it took someone to lose an arm for me to realize the danger I put myself and my researcher at…. I know better. — Where I work, an experiment of this type would never be allowed to become operational until a subject matter expert (or probably a team of them, in this case) fully inspected the design and the operating parameters. Especially if the system was built by a new member of a research team. A full hazard control plan, in writing, would be written up and signed off by anyone touching the experiment. In my world, the subject matter experts are drawn from research scientists familiar with the experimental designs. Since it was a pressurized system containing an explosive hydrogen gas mixture, I suspect that at minimum, there would be an emphasis on a design that minimized risk including volume limits, an inspection for electrical safety, and likely, some sort of containment system would be incorporated to protect against just this sort of catastrophe. A reviewer would probably ask “is there a safer way to introduce the gas mixture into the reactor?”. These sorts of intensive safety programs add time and cost to the business of doing science (but are ubiquitous in industry and government labs), but the flip side is what we see in these pictures: when...

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U Hawaii story now has photos
Apr22

U Hawaii story now has photos

Just a quick FYI to Safety Zone readers to note that my U Hawaii story from earlier this week, “Spark from pressure gauge caused University of Hawaii explosion, fire department says,” now has photos provided by the Honolulu Fire Department.

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Spark from pressure gauge caused University of Hawaii explosion
Apr20

Spark from pressure gauge caused University of Hawaii explosion

From my story at C&EN: An explosion last month that caused a University of Hawaii, Manoa, postdoctoral researcher to lose an arm was caused by a spark from a digital pressure gauge that was not designed for use with flammable gases, says a Honolulu Fire Department investigation report. Go read the story for more, including some context about how the lab’s experimental set-up seems to have changed, based on a prior publication from the lab compared to what Ekins-Coward and the PI told investigators. The University of California Center for Laboratory Safety investigation report is expected to be finished by the end of this month. The Hawaii Occupational Safety & Health Division is also investigating the incident. Other coverage and commentary: U Hawaii story with recording of press briefing – Investigation continues into lab explosion at UH Chemjobber – More details on the UH-Manoa incident: explosion probably due to sparking pressure gauge KHON – Investigating entity hired by UH founded after similar laboratory explosion (KHON and other Hawaiian news organizations also had other stories, but this one went beyond just reporting the facts in the fire department report) Science – University of Hawaii lab explosion caused by inappropriate gauge Chemistry World – Hawaii lab explosion linked to safety failings Curiosity Science – Dear chemists: Please be...

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Omission of experimental step was cause of explosion at Texas Tech
Apr13

Omission of experimental step was cause of explosion at Texas Tech

An undergraduate researcher was injured at Texas Tech University on March 10, when a “vial exploded while the student was collecting a dry precipitate powder with a metal spatula,” according to the Texas Tech “lessons learned” report about the incident. The student and others in the lab were all wearing appropriate personal protective equipment, and the student suffered only superficial injuries, the report says. “The cause of the accident is believed to be an omission of a hydrochloric acid precipitation step during the recreation of a synthesis reaction taken from literature,” the report says. “This allowed the unintentional formation of a diazonium salt that exploded during collection for further analysis.” Texas Tech’s recommended actions to prevent something similar from happening in the future: Researchers working on synthesis reactions with anticipated energetic products or intermediates need to be cautious of products created during the reaction series. As part of a regular hazard analysis conducted at the outset of experimental work, researchers should review and update their Standard Operating Procedures (SOPs) to incorporate the possible hazard(s) of intermediate products. In this case, the intermediate product should have been identified as energetic on the basis of the reaction series being run. All work with potentially energetic materials should be performed with plastic tools to reduce the possibility of friction and static discharge creating an initiating spark. The University of California, Berkeley, also had a metal spatula versus diazonium compound explosion last year, although in that case the graduate student involved in the incident knew he was working with a diazonium perchlorate. He was also not wearing appropriate eye protection, and porcelain funnel fragments lacerated one of his...

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