Human Resources
Human Resources
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Formic Acid Explosion and Explosive Laboratory Chemicals11. (1990)Report of Formic Acid Explosion at Sydney UniversityThe enclosed information was submitted by Kevin Lonsdale, RSPhysSE and confirmed by Henry Satrapa, RSC. The letter was published in Chemical & Engineering News Nov 13, 1989, and is reproduced for information and action.
SIR: A storeman recently lost an eye when an E. Merck of Darmstadt, West Germany, 1-L bottle of 98 to 100% formic acid exploded as he lifted it off the shelf in the main store of this chemistry school. He was not wearing safety glasses. Concentrated formic acid slowly decomposes to carbon monoxide and water upon prolonged storage, and the gas pressure can be sufficient to rupture sealed glass containers. It happens that none of the academic or technical staff members of the school were aware of this hazard. The first descriptions in the general safety literature appear to have been in the second edition of L. Bretherick's "Handbook of Reactive Chemical Hazards" [Butterworths, London, page 298 (1979)] and the third edition of "Hazards in the Chemical Laboratory" [Royal Society of Chemistry, page 339 (1981)]. Merck recognised the problem some years ago, and in 1984 changed the ordinary white screw cap to a black cap incorporating a degassing valve. The significance of the change was, however, not widely communicated to their customers in this region. The bottle that exploded here was the old type with a white cap. The purpose of this note is to advise chemists to check their stocks of 98 to 100% formic acid. Any bottle from Merck or other suppliers that does not have a pressure relief valve in the cap should be made safe by gently unscrewing the cap. This should be done only while wearing a face shield, goggles, and heavy-duty gloves and overalls with another person standing by in the event of an explosion. Such old stock should also be used soon. Our experience reinforces the desirability of wearing safety glasses whenever chemicals are being handled. A. V. Robertson Laboratory Chemicals that are Explosives(or have the potential to become explosives on deterioration) The following list is reproduced from M.J. Pitt and E. Pitt, Handbook of Laboratory Waste Disposal, Ellis Horwood Publisher, UK, 1985. Formic acid has been added to the list. Appendix C-4 Explosive Chemicals The following may be supplied as laboratory reagents, pharmaceuticals, or polymer components. However, they are in fact explosives. Appropriate care should be taken in storage and disposal, especially if they have deteriorated in any way. acetylene Appendix C-6 Deteriorated Chemicals The following is a selection of chemical substances which can deteriorate to a dangerous condition with age, under common storage conditions. The degree of the hazard will vary considerably with age and the exact situation, but it is advisable to take precautions when discarding, recycling or otherwise handling old samples. Acetal (3) Benzenesulphonyl chloride (5) Calcium carbide (5) Decahydronaphthalene (3) Ether (3) Formic acid (5) Glycidyl n-butyl ether (3) Hydrogen peroxide (5) Iodine pentoxide (4) Lauroyl peroxide (5) Magnesium perchlorate (4) Nitric acid (5) Peracetic acid (1,4,5) Silicon tetrachloride (5) Tetrahydrofuran (3) Urea nitrate (4) Vinyl acetate (3) Zinc (5) Key (1) Can deteriorate to a shock-sensitive explosive. Take exceptional care if there is evidence of drying out, crystallisation or contamination. It may be very dangerous to attempt to open the container. (2) Forms peroxides, especially on exposure to air and light, making the material liable to explode. This class is so dangerous that it should not normally be distilled unless it has been very well controlled. Material more than one year old should be discarded, even if unopened. Containers should not be opened if there is any solid visible around the closure or any evidence of crystals inside. (3) Also forms peroxides. If very old or obviously in poor condition treat as (2). Otherwise take care to test for peroxides before use or recovery procedures. (4) High energy materials which are sensitive to the presence of dust. Clean the outside of containers before opening. If in doubt, do not open. Mixtures of the material with dust, paper or organics may ignite or detonate when exposed to friction, e.g on the threads of a screw-capped container. (5) Containers may have a high internal gas pressure, owning to decomposition. Open carefully behind a safety shield in a fume cupboard. For further information contact: |