Our friends at Hazworld remind us of the dangers to workers that can arise from spillages and leakages of chemicals and point out that some of the nastiest chemicals have a lethal effect on humans at concentrations below levels at which they can be smelt. which they can be detected by smell. Hydrogen cyanide is one such compound. Although, as it is said to have an almond-like odour, at least one person must have smelt it and lived to tell the tale.

The story starts with a policeman in Texas who stopped a tanker on US highway 59 because vapour was escaping from the top of the truck. The officer and the truck's driver inspected the truck but found no apparent problems - in particular there was no noticeable chemical smell - the driver was allowed to continue his journey. According to the local police chief, shortly after the incident the officer began to suffer from eye irritation and nausea. He was taken to hospital and the police department alerted law enforcement agencies across a wide area to look out for the tanker. When the tanker was eventually stopped, it was found to be leaking inhibited ethyl acrylate.

The policeman was fortunate because the odour of ethyl acrylate can be detected at levels of concentration lower than is needed to cause serious harm to human beings. In other words, the amount that was leaking was insufficient to be lethal but still enough to cause the officer some discomfort. However, this is not always the case as some volatile compounds are highly toxic if the vapour is inhaled. The compounds may be fatal to humans at concentrations below levels at

It is human nature to use smell when investigating an incident, but it is of the utmost importance that chemicals or leaking packages or containers should not be sniffed Follow the example of President Clinton, and do not inhale! Be on the safe side, evacuate the area and call in the emergency services with their specialist detection equipment.

More details from

http://www.hazworld.com