US Department of Transportation sign for Class 1.1 <a href="https://en.wikipedia.org/wiki/Dangerous_goods#Classification_and_labeling_summary_tables" class="extiw" title="en:Dangerous goods">dangerous goods</a>
<a href="//commons.wikimedia.org/wiki/User:Ch1902" title="User:Ch1902">Ch1902</a>
2012-01-03
<a rel="nofollow" class="external free" href="http://phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/erg2008_eng.pdf">http://phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/erg2008_eng.pdf</a>