Cobra in action

School in danger: alarm about highly explosive acid

Picric acid was found in Oberschützen.

(Bild: thinkstockphotos.de, krone.at-Grafik)

Danger lurks in school chemistry laboratories. If stored incorrectly, delicate substances can turn into high-risk materials. Explosive picric acid recently caused alarm bells to ring in the Oberwart district. Specialists from the Cobra task force defused the situation.

Picric acid is harmless when wet, but when dry the chemical mixture is considered highly explosive. Even minor vibrations or unscrewing the container can be enough to cause a violent detonation.

HTL was evacuated
The HTL Mödling in Lower Austria was confronted with this sobering realization just a month ago. When the dried substance was discovered in the workshop laboratory, 250 students had to leave the building. The defusing service of the Ministry of the Interior, the pollutant advisory service of the Lower Austrian regional fire brigade association and regional chemists were deployed.

Acid found in Oberschützen
Similarly explosive incidents repeatedly trigger the evacuation of schools in eastern Austria. As a warning, directorates are called upon to regularly check their chemical stocks. Explosive picric acid was also found in a darkened 0.5-liter glass bottle in the poison cabinet of the locked laboratory at the Bundesrealgymnasium in Oberschützen.

Picric acid (2,4,6-trinitrophenol) is a chemical compound with a benzene body as its basic structure. Outside of schools, the substance is used in the manufacture of explosives, matches and electric batteries. The substance can also be used in the etching of copper and in the production of colored glass, in the leather industry and in the synthesis of dyes. In medicine, its importance is limited to histology procedures. Picric acid irritates the eyes and mucous membranes. In teaching, the unstable, inflammatory substance is used in a less reactive form.

"Risk substance to be disposed of by a specialist company"
All the authorities were immediately on high alert, supported by an experienced environmental chemist from the Pinkafeld municipal fire department's southern hazardous substances unit. With the help of specialists from the Cobra task force, it was possible to defuse the flammable acid.

What remained was a substance that was no longer explosive, but highly toxic. An expert on site: "The school management should have the hazardous substance disposed of immediately by a specialist company, even though the costs involved in removing it are enormous."