Diacetyl

A number of workers in the popcorn industry in the USA have developed severe lung disease after inhaling fumes from a flavouring agent known as diacetyl (2-3-butanedione) which imparts a butter flavour to food. In its pure form diacetyl is a green-yellow coloured liquid which gives off fumes, especially when heated. Although safe for humans when eaten in the small amounts permitted in the final food product, workers mixing the liquid in concentrated bulk form before adding to foodstuffs can be exposed to vapour that is extremely irritating to the eyes, nose, throat and lungs. In some cases permanent lung damage may occur when the small airways in the lungs become blocked by inflammation.

The extent of diacetyl use for flavouring food and drink products in GB is uncertain. Where it is used, worker exposure to fumes must be controlled in accordance with the Control of Substances Hazardous to Health (COSHH) Regulations. Under these regulations there is a hierarchy of control - (1) substitution with a safer chemical where possible, (2) containment within sealed plant, (3) effective fume extraction and, if none of these are possible, then goggles and suitable respiratory protective equipment. In addition workers handling diacetyl need to be informed of the hazards/risks and be provided with appropriate training.