From the archives: Chemists lose hands from peroxide explosions
Feb21

From the archives: Chemists lose hands from peroxide explosions

Regarding the inadvertent synthesis of TATP at the University of Bristol, someone commented at “In The Pipeline”: I recall a C&EN story from the early 1980s about a group at K (Kansas or Kentucky?) preparing a batch of 100% H2O2. It exploded during purification and blew off a corner of the building. I vaguely recall a picture of the lab walls completely blown out. I believe they (Kansas? Kentucky?) shut down their chemistry program after that incident before restoring it after a couple of years. I dug into our archives to see if I could find the incident in question. I haven’t been able to find it, but I did dig up some other interesting stories: From July 21, 1952: Chemist Loses Hand in Performic Acid Explosion Five milliliters of performic acid exploded recently at Laval University, Quebec, Canada, tearing off the right hand of a graduate student and smashing all glassware in a radius of 2 to 3 feet. Numerous glass slivers were driven into his skin and into one of his eyes. According to information from the student, A. Weingartshofer-Olmos, and Paul A. Giguere, professor of physical chemistry at Laval, a small receiving flask containing the 5 ml of approximately 90% performic acid was being removed from the still when it detonated for no apparent reason. The acid had been prepared by the addition of 25 grams of 99% hydrogen peroxide to 20 grams of 99% formic acid in the presence of 6.5 grams of concentrated sulfuric acid as catalyst. After two hours for reaching equilibrium, the mixture was distilled under reduced pressure (5 to 10 mm Hg) at 30° to 35° C. This preparation had been performed several times before in the same manner without any mishap. The material was known to be dangerous and adequate precautions were taken. All glassware was thoroughly cleaned in fuming sulfuric acid. The distillation apparatus was entirely assembled through ground glass joints and no lubricant of any sort was used. The still was connected to a dry-ice trap, manometer, and vacuum pump through a length of Tygon tubing. Only 5 to 10 milliliters of the acid was prepared at a time. As nothing unusual had happened while the material was heated for distillation and as the distillate was kept at —10° to — 15° C , the operator felt that the danger period was over. He removed his face shield, pushed aside the two safety screens, and reached for the receiving flask. As he was about to touch the discharge tube to collect a pendant drop, the flask exploded. Like all peroxides and ozonides, performic acid is unstable, since it...

Read More
How a student unintentionally made an explosive at U Bristol
Feb15

How a student unintentionally made an explosive at U Bristol

Last week, the Safety Zone reported that a University of Bristol student had unintentionally made approximately 40 g of triacetone triperoxide (TATP), prompting building evacuations and a controlled detonation by an explosives team. Here’s a statement about the incident, prepared by Timothy C. Gallagher, a chemistry professor and dean of the Faculty of Science, and Nicholas C. Norman, head of the school of chemistry. On 3 February 2017, a graduate student in the School of Chemistry at the University of Bristol was carrying out a literature procedure to oxidise an aldehyde to the carboxylic acid using aqueous acidified chlorite. The experiment was carried out on a 5 mmol scale (just under 1g of aldehyde) and risk assessments identifying all hazards had been undertaken and signed off by both student and supervisor. The reaction solvent was acetone (50 mL). Part of the procedure involved adding a quantity of 30% hydrogen peroxide (H2O2) solution to remove some of the by-products of the reaction, whose presence was (apparently) associated with a yellow colour (possibly including chlorine dioxide). The literature indicated that H2O2 be added until this yellow colour had disappeared, which should have required about 1 mL of peroxide solution. The student, focusing on the yellow colour, which did not completely disappear, continued to add hydrogen peroxide solution until about 50 mL had been added. During workup to remove the solvent, the student realised that the solvent volume was not decreasing and that the liquid was becoming viscous, and so likely contained far more “product” than was expected. GCMS analysis indicated the presence of triacetone triperoxide (TATP), and it was estimated that this could amount to 30-40g if all the excess H2O2 had reacted with the acetone solvent. At that point, the graduate student immediately alerted the supervisor, who escalated this to the Head of School. A series of decisions were made and actions taken that resulted in the disposal of the suspected TATP by means of a controlled explosion carried out by the emergency services. Nobody was injured and no damage was done in the lab. Although the TATP presented an explosion hazard, the risk of explosion was considered minor due to all material remaining in solution; TATP is far more sensitive to detonation as a solid. Immediate disposal was warranted, however, due to the risk of precipitation/crystallisation of a solid material. There are lessons to be learned from what happened and some messages. First, the student was concerned with adding hydrogen peroxide to remove the yellow colour (due, at least in part, to chlorine dioxide, which is itself a hazardous material), but overlooked the much greater hazard of adding a...

Read More
Color-blindness as a lab safety concern?
Feb08

Color-blindness as a lab safety concern?

This week’s C&EN includes a Newscripts column about new eyeglasses for color-blind people that enhance color perception. I was struck by these comments by a materials science graduate student who tried the glasses: “Primary colors seemed more their color,” [Patrick] Stanley reports of his time wearing the glasses. “Labels and boxes caught my attention more—and I guess the point of a hazardous label is to catch my attention.” He also could tell the difference between red and green LEDs and felt more adept at color-matching tasks such as tracing gas lines and reading graphs. “I found myself being quicker in making color assertions,” he says. I’d never considered before whether color-blindness might be a lab safety concern. What do you think? Are there labs in which eyeglasses such as these might be helpful to ensure safety? (Combined with appropriate safety glasses or goggles, of...

Read More
Student unintentionally makes explosive at University of Bristol
Feb07

Student unintentionally makes explosive at University of Bristol

A University of Bristol graduate student inadvertently synthesized approximately 40 g of triacetone triperoxide (TATP) on Friday, prompting building evacuations and a controlled detonation by an explosives team, chemistry professor and Faculty of Science dean Timothy C. Gallagher has confirmed to C&EN. No one was injured in the incident. The TATP was in solution and not isolated as a solid. When the student realized what had happened, the student handled the situation very responsibly, Gallagher says. Further response by the department, university, and emergency personnel “went like clockwork,” Gallagher adds. Gallagher says that he is “absolutely convinced” that the preparation of TATP was unintentional rather than deliberate or with malicious intent. Gallagher and others at the university are working to understand exactly how the student came to make the explosive, especially in such quantity. Once that is done, Gallagher plans to share more details and all lessons learned with the chemistry community. “It’s the right thing to do,” he says. Chemist commentary: Chemjobber, Reddit Local news coverage: Epigram (student newspaper), Bristol Post,...

Read More
Safety correction in JACS
Feb02

Safety correction in JACS

A few weeks ago, “Kenrod” left this comment on my post about the new safety policy for ACS journals: So check out the Experimental in the Supporting Information of this Communication in the very first JACS issue of 2017: J. Am. Chem. Soc., 2017, 139 (1), 19; http://pubs.acs.org/doi/full/10.1021/jacs.6b09889 The first two procedures describe the prepn of trinitroaniline (TNA) and triaminotrinitrobenzene (TATB). Both are known explosives. No hazard warnings whatsoever, not even a peep. The paper was reviewed and published before the new policy went into effect. Nevertheless, I contacted JACS editor Peter Stang to ask him about it–in particular, how he’d like to see these sort of safety hazards addressed in JACS in the future. Stang first noted that he did not handle this particular paper, because it was authored some of his colleagues at the University of Utah. That acknowledged, “Clearly safety is an absolutely critical issue, and it’s also a very complex issue,” he said. He pointed to one source of complexity as quantity, because there may be different safety concerns depending on whether you’re making a few milligrams, a few grams, or several kilograms of a particular compound. Another source of complexity is that toxicity is difficult to determine when a brand new compound is synthesized. “To do toxicity tests on every new compound made is not feasible,” Stang said. However, when there are known safety issues, such as in the above paper, “we will require authors to provide a warning, even if they don’t know the full details or extent of toxicity, explosiveness, or other properties,” Stang said. And to that end, JACS has now issued a correction to the paper that adds this to the materials and experimental methods sections of the supporting information: Warning: 2,4,6-Trinitroaniline (TNA) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) are very sensitive and highly explosive. They should be handled with extreme...

Read More