Diacetyl is imported predominantly for use in formulations in the food flavouring industry. There have been reports, mainly in the USA, of damage to the respiratory system caused by inhalation. This report presents the findings of a small study to investigate exposures to diacetyl amongst workers employed in the food flavouring and fragrance industries. The report also includes from previous HSE/HSL visits.
Exposures to diacetyl are generally of short duration, nonetheless, there is potential for workers to be exposed to airborne levels above those recommended by the EU Scientific Committee on Occupational Exposure Limits (SCOEL) of 0.1ppm (8-hour TWA) at the time of the study. Following completion of this report, EU (SCOEL) have tabled new proposed limits of 0.02 ppm (8-hour TWA) and 0.1 ppm (15-minute TWA). There is currently no UK Workplace Exposure Limit (WEL). Personal exposures to diacetyl for this study ranged from 0.01ppm to 1.7 ppm (8hr TWA) and 0.09ppm to 0.33ppm (15min TWA).
Local exhaust ventilation (LEV) was provided during most diacetyl processes. The effectiveness of LEV control was variable. This was mostly due to inappropriate LEV hood design relative to the process.
The respiratory protective equipment (RPE) used was, in most cases, the correct type, however in some cases the assigned protection factors offered (10 & 20) may not reduce exposures to below the SCOEL proposed limits. Deficiencies in the face-fit testing, training and management of RPE were noted. Recommendations refer to hierarchy of control measures including procedural measures, and currently available HSE guidance.
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