Toxicological Trivia fron February 10, 2010: The derailment and subsequent fire on a freight train carrying a chemical substance in Ukraine caused a toxic cloud of 90 square kilometers which threatened to 14 villages in the Lviv region, west of the country in July 2007. The substance that transported  was:
a) Phosphorus, yellow liquid;
b) White phosphorus;
c) Hydrocyanic acid.

Correct Answer a. Read more in Spanish news: Alarm in Ukraine by a toxic cloud