13:34

Tom Phillips highlights an alarming report in the Beijing News which claims that the warehouse at the centre of the blasts was storing at least 700 tonnes of the poison sodium cyanide.

According to Center for Disease Control and Prevention this is a “highly toxic chemical asphyxiant” and exposure to it can be “rapidly fatal”.

It has whole-body (systemic) effects, particularly affecting those organ systems most sensitive to low oxygen levels: the central nervous system (brain), the cardiovascular system (heart and blood vessels), and the pulmonary system (lungs). Sodium cyanide is used commercially for fumigation, electroplating, extracting gold and silver from ores, and chemical manufacturing. Hydrogen cyanide gas released by sodium cyanide has a distinctive bitter almond odor (others describe a musty “old sneakers smell”).

The CDC guidance on how the emergency workers should respond to a leak of the chemical helps explain why Beijing sent a 217-strong team of “Nuclear, Biological and Chemical specialist to the scene (see earlier).

Responders should use a NIOSH-certified Chemical, Biological, Radiological, Nuclear (CBRN) Self Contained Breathing Apparatus (SCBA) with a Level A protective suit when entering an area with an unknown contaminant or when entering an area where the concentration of the contaminant is unknown. Level A protection should be used until monitoring results confirm the contaminant and the concentration of the contaminant.