Environment Report 2015

40 / 64

ENVIRONMENT REPORT 2015
page 40
5. Accidental Oil and Chemical Releases
5.1 Introduction
The oil and gas industry does its utmost to prevent accidental oil and chemical releases by investing heavily in
the provision of physical barriers, such as downhole safety valves, maintenance to prevent leaks, as well as in the
development of handling procedures and staff training.
Offshore hydrocarbon (oil and gas) releases must be reported to the Health and Safety Executive (HSE) and all
offshore hydrocarbon and chemical releases, regardless of size, that reach the marine environment must be
reported to DECC through the submission of a Petroleum Operations Notice 1 (PON1). PON1 data are published
on DECC’s website45 and updated regularly. The following analysis is based on the PON1 dataset and presents
an overview of the number and mass (excluding the mass of those releases still classified as ‘under review’) of
accidental releases on the UKCS in 2014 and over the past decade.
Further analysis has been carried out to categorise PON1 data from 2010 to 2014 by source and cause of accidental
releases, as well as by hazard to the marine environment for the chemical releases.
Although the number of releases can appear significant, it is important to note that the UK offshore oil and gas
industry is committed to transparency in reporting. All releases to the marine environment, no matter how
small, are reportable as a PON1. Given that the releases are unplanned, they cannot always be measured and a
worst case estimation is used to determine a release amount; the amount actually released is often lower than
that reported.
5.2 Overview from 2003 to 2014
There is no clear trend in the amount of chemical and oil releases to the marine environment over the last
11 years, highlighting the sensitivity of these data to single, low incidence, high mass events, as shown in the blue
and red peaks in Figure 26 opposite. There is, however, a marked decline in the amount released accidentally in
recent years, with the mass of chemical releases falling sharply since 2009 and oil releases since 2010. 2014 had
the smallest mass of accidental releases on record, with no individual releases greater than ten tonnes of oil or
200 tonnes of chemicals.
The total amount of oil and chemicals accidentally released on the UKCS in 2014 is also small relative to the total
mass discharged to sea from assets under permits (see Section 3). Many of the categories used to break down
these data are dominated by a relatively small number of larger releases.
45 The DECC PON1 data are available at