Argentina - Fire Forms Toxic Cloud - NYTimes.com A public scare over a toxic cloud that formed Thursday prompted the evacuation of offices, schools and the central train station in Buenos Aires, and sent about 80 people to seek emergency treatment. The government declared a public health emergency after a shipping container from China carrying a pesticide caught fire at a Buenos Aires port, sending a thick, foul-smelling cloud of smoke over several parts of the city. An emergency official recommended that people living near the site of the fire "avoid going out" and "close doors and windows." A laboratory analysis identified the active ingredient in the pesticide as thiodicarb, classified as "moderately hazardous" by the World Health Organization in 2009. Sergio Berni, the security secretary, said a sample of the pesticide was "of low toxicity" and posed little risk.