ICI handles and processes many different materials. If released, each may have an impact on the environment. To create a measure of ICI’s overall environmental impact, we group emissions of individual substances into six categories of ‘environmental burden’:
- Global warming,
- photochemical ozone creation,
- ozone depletion
- aquatic oxygen demand,
- hazardous air emissions, and
- acidity to air.
For more details see ICI's Environmental Burden booklet.
Burden factors
In 2005 we reviewed the burden factors used for individual substances in line with international standards, and have incorporated some changes for Greenhouse gases and Hazardous air emissions into the 2005 baseline and 2006 data.
Greenhouse gases (reference substance Carbon Dioxide)
Source: IPPC Third Assessment Report 2001
Increased burden factors: Methane: 21 to 23; Nitrous oxide: 310 to 296;
These changes have made <0.01% difference to our reported absolute data in 2006
Hazardous air emissions (reference substance Benzene)
Source: UK Health & Safety Executive EH40, rev 2005’
In 2005 the Health and Safety Executive revised EH40 and replaced Occupational Exposure Limits (OEL) with Workplace Exposure Limits (WEL). At the same time the WEL of Benzene was reduced from 9.74 to 3.25 mg/m3.
Since Benzene is the reference substance all the absolute burden amounts appear smaller.
This change has reduced the absolute reported burden by 34%, but does not alter the improvement reported per tonne of product.
Portfolio changes and 2005 baseline
Changes in our overall business portfolio can also distort trends when measurements are being compared with the 2005 baseline (for the % improvement/reduction targets).
So when we acquire a business we adjust the baseline by adding its data retrospectively to the 2005 figure. In subsequent years, its data is treated in the same way as data from other parts of the ICI Group. If we sell a business or part of a business, its data is removed from the baseline and subsequent years. But if a site is closed, we make no changes to the baseline.
While we make these adjustments to the baseline when we report our performance for the current year, we do not adjust the reported performance for the years already reported.
Adjustment for product mix
Our Sustainability Challenge 2010 objectives in the environmental area are based on percentage reductions from the 2005 burden values per tonne of production. We have a diverse and changing product portfolio so a simple percentage change in a measure of impact per tonne of production could be a misleading guide to performance: the difference might have been due solely to changes in the quantities of individual products manufactured.
So each year we report the percentage change from the baseline year (2005) adjusted to the current year’s product mix. This more accurately reflects the actual changes in our performance.
Historic performance
We report our progress against five year Challenge targets, but we recognize that this does not give a picture of the overall improvement achieved since 1990. So we have incorporated some additional information into this report:
• Overall footprint: we publish a diagram showing the percentage change in absolute tonnes of burden at the end of each Challenge period. This is not adjusted for portfolio changes across Challenge periods.
• 2000 performance: the progress graphs now show the 2000 level as well as the current Challenge period. This data is based on the performance improvement achieved during the Challenge 2005 period, with the 2005 portfolio, but has not been adjusted for subsequent changes in portfolio.
