OCNS Bulletin Board

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Related information

DTI: UK Government Department for Trade and Industry www.dti.gov.uk

OSPAR: Oslo and Paris Commission www.ospar.org

Hazard Assessment

CHARM

The OCNS conducts hazard assessments on chemical products that are used offshore. The CHARM model calculates the ratio of Predicted Effect Concentration against No Effect Concentration (PEC: NEC), and is expressed as a Hazard Quotient (HQ), which is then used to rank the product. The HQ is converted to a colour banding (see table 1 below), which is then published on the Definitive Ranked Lists of Approved Products, Adobe Acrobat format (ZIP, 1.84 MB, updated 6 May 2008).

Data used in the CHARM assessment include toxicity, biodegradation and bioaccumulation.

The CHARM model is divided into 4 main algorithms
•Production
•Completion / Workover
•Drilling
•Cementing

Table 1. The OCNS HQ and colour bands

Minimum HQ value	Maximum HQ value	Colour banding
>0	<1	Gold	Lowest Hazard Highest Hazard
≥1	<30	Silver
≥30	<100	White
≥100	<300	Blue
≥300	<1000	Orange
≥1000		Purple

Non-CHARM

Products not applicable to CHARM model (i.e. inorganic substances, hydraulic fluids or chemicals used only in pipelines) are assigned an OCNS grouping A – E, with A being the greatest potential environmental hazard and E being the least (see below table)

Products that only contain substances termed PLONORs (Pose Little or No Risk) are given the OCNS E grouping (LINK to PLONOR list).

Data used in the assessment includes the following:

Toxicity for initial grouping
Biodegradation and bioaccumulation data are used to assign the final OCNS letter

Table 2. The OCNS letter grouping

Initial OCNS grouping	Result for aquatic toxicity (mg/l)	Result for sediment toxicity (mg/l)
A	<1	<10
B	>1 - 10	>10 - 100
C	>10 - 100	>100 - 1,000
D	>100 - 1,000	>1,000 - 10,000
E	>1,000	>10,000