Editing Picric acid (section)

==Safety==
Modern safety precautions recommend storing picric acid wet, to minimize the danger of explosion. Dry picric acid is relatively sensitive to [[Shock (mechanics)|shock]] and [[friction]], so laboratories that use it store it in bottles under a layer of [[water (molecule)|water]], rendering it safe. Glass or plastic bottles are required, as picric acid can easily form metal [[picrate]] salts that are even more sensitive and hazardous than the acid itself. Industrially, picric acid is especially hazardous because it is volatile and slowly sublimes even at room temperature. Over time, the buildup of picrates on exposed metal surfaces can constitute an explosion hazard.<ref>{{cite web |title=Picric Acid, Wet |website=hazard.com |date=21 April 1998 |url=http://hazard.com/msds/mf/baker/baker/files/p4556.htm |access-date=13 April 2021}}</ref>

Picric acid gauze, if found in antique first aid kits, presents a safety hazard because picric acid of that vintage (60–90 years old) will have become crystallized and unstable,<ref>{{cite news |last1=Harding |first1=Evan |last2=Searle |first2=Jamie |date=7 July 2021 |title=Potentially explosive substance was in Catlins museum for decades |url=https://www.stuff.co.nz/national/125677951/potentially-explosive-substance-was-in-catlins-museum-for-decades |work=Stuff |access-date=20 July 2021}}</ref> and may have formed metal picrates from long storage in a metal first aid case.

[[Bomb disposal]] units are often called to dispose of picric acid if it has dried out.<ref>{{cite web|url= http://www.irishtimes.com/newspaper/breaking/2010/1001/breaking49.html|title= Bomb squad called to Dublin lab|date= 1 October 2010|work= irishtimes.com|publisher= Irish Times|access-date= 22 July 2011|archive-date= 22 October 2012|archive-url= https://web.archive.org/web/20121022045304/http://www.irishtimes.com/newspaper/breaking/2010/1001/breaking49.html|url-status= dead}}</ref><ref>{{cite web |url= http://www.rte.ie/news/2010/1103/teagasc.html|title= Unstable chemicals made safe by army|date= 3 November 2010|work= rte.ie|publisher= RTÉ News|access-date=22 July 2011}}</ref> In the United States there was an effort to remove dried picric acid containers from high school laboratories during the 1980s.{{Citation needed|date=October 2024}} 

[[Munitions]] containing picric acid may be found in sunken [[warships]]. The buildup of metal picrates over time renders them shock-sensitive and extremely hazardous. It is recommended that [[shipwreck]]s that contain such munitions not be disturbed in any way.<ref name="allbright78">Albright, p.78</ref> The hazard may subside when the shells become corroded enough to admit [[seawater]] as these materials are water-soluble.<ref name="allbright78" /> Currently there are various fluorescent probes to sense and detect picric acid in very minute quantities.<ref>{{cite journal |last1=Arunkumar |first1=Chellaiah |last2=Sujatha |first2=Subramaniam |title=Protonation and axial ligation intervened fluorescence turn-off sensing of picric acid in freebase and tin(iv) porphyrins |journal=RSC Advances |date=26 Oct 2015 |volume=5 |issue=113 |page=93243 |doi=10.1039/C5RA18310C |bibcode=2015RSCAd...593243S |url=https://pubs.rsc.org/en/content/articlelanding/2015/ra/c5ra18310c}}</ref>