Picric Acid: The Flammable Chemical Once Used for Medicinal Properties

It is rare that an agent once used for medical purposes requires a call to the bomb squad for disposal.¹ Colloquially known as picric acid, 2,4,6-trinitrophenol is such an agent.² Historically, the chemical served as a topical agent for relief of superficial burns and scalds.³ Today, the nitroaromatic compound that is related to TNT leans toward industrial, and military applications. These include serving in boosters, fuses, and rocket fuel.²

Prior to these wider-scale martial uses, picric acid’s medicinal properties were described in 19th and 20th century medical literature. An 1896 article published in the British Medical Journal describes the soaking of sterilized gauze in a picric acid solution to relieve patients’ burns in both inpatient and outpatient settings.³ A similar technique was also described in a 1920 article to treat pedal epidermophyton infection.⁴ The mechanisms that lent to benefits in burn relief are 2-fold: the numbing of pain and albumin coagulation that decreased pus formation.³

The latter mechanism led to surgical uses described in a 1911 Journal of American Medicine article. The 'bitter' and yellow substance’s risk for detonation was identified in the same publication, describing the precipitation of picric acid’s potassium and sodium salts as explosive.⁵

Conclusion

Picric acid required removal from educational and laboratory sites as recently as 2014, after discovery in storage as a forgotten chemical. Individuals who come across dry, old, yellow powder should take care to go through the appropriate routes of alerting and disposal to avoid risks that accompany picric acid use.

References

• Picric acid canister blown up by bomb squad in Bradford. BBC News. bbc.co.uk/news/uk-england-leeds-30040074. Published November 14, 2014. Accessed March 29, 2018.
• U.S. Army Center for Health Promotion and Preventive Medicine. Wildlife toxicity assessment of picric acid (2,4,6-trinitrophenol). Published August 2005. usaphcapps.amedd.army.mil/erawg/tox/files/PicricAcid(final05).pdf. Accessed March 29, 2018.
• Power D. A note on picric acid in the treatment of superficial burns and scalds. Br Med J. 1896;2(1863): 651.
• Weiss RS. Picric acid in the treatment of severe epidermophyton infection. Arch Derm Syphilol. 1921;3(4):413-414. doi:10.1001/archderm.1921.02350160068006.
• Ehrenfried A. Picric acid and its surgical applications. JAMA. 1911;56(6):412-415. doi:10.1001/jama.1911.02560060022007.