Southall Gasworks

Public Health findings

Following concerns about odour from the Southall Gasworks site the council asked Public Health England (PHE) to carry out an independent health risk assessment using the air quality monitoring data collected from the VOC monitoring stations at the development site. 

PHE has published three reports which show that it is unlikely that there is a direct toxicological risk to the long-term health of the nearby population. Air quality monitoring at this site is continuing and is being reviewed by PHE on an ongoing basis.

The data provided to PHE by the council has been compared to available health-based air quality guidelines and standards or assessments levels; these standards are for the protection of the general population and are often at lower levels than the standards for occupational exposure. 

Based on the monitoring data, average levels of VOCs have been below or comparable to guideline or assessment levels. However, it is recognised that strong odours can lead to people experiencing short term reactions such as nausea, headaches or dizziness even when the substances causing the odours are not themselves harmful to an individual’s long-term health.

There have been occasions where levels of benzene, naphthalene and 4-isopropytluene have been recorded above the health-based guidelines. These exceedances have been short lived and are mostly at monitoring locations immediately adjacent to the soil hospital. The exceedances have also remained below levels that are likely to cause acute or short-term health effects.

PHE have carried out three interim risk assessments.  The first interim risk assessment was based on air quality monitoring undertaken between 1 June and 25 September 2018 and the second was based on air quality monitoring undertaken between 25 September and 12 December 2018. The latest report and risk assessment have been updated following the receipt of additional air quality monitoring data undertaken between 12 December 2018 and 10 May 2019. 

View full details of the latest report and and risk assessment.

Further monitoring data has been received and will be used to update PHE’s risk assessment in due course.