Hazard Assessment Process
Chemical Hazard and Risk Management (CHARM)
Hazard assessment of offshore chemicals is performed on the basis of the OSPAR Harmonised Mandatory Control Scheme (HMCS). Chemicals are ranked according to their calculated Hazard Quotients (HQ) by the CHARM (Chemical Hazard Assessment and Risk Management) mathematical model, which uses toxicity, biodegradation and bioaccumulation data provided by suppliers on the HOCNF form.
The HQ is converted to a colour banding, as illustrated in Table 1 . Assessed products are published on the Definitive Ranked Lists of Registered Products in Excel format which is updated bi-weekly.
Table 1: OCNS HQ and colour bands
|Minimum HQ value
|Maximum HQ value
The CHARM model is divided into four main algorithms:
More information related to the specific CHARM algorithms and their use in offshore chemical registration can be found in section 1.4 of part 1 of the OSPAR Guidelines for Completing the HOCNF.
Please note- if the submitted chemical is not suitable for assessment by CHARM, advice should be sought from Cefas on what information is required on the HOCNF, to allow assessment by other mathematical models.
Products not amenable to the CHARM model (i.e. inorganic substances, hydraulic fluids, pipe dopes or chemicals used only in export pipelines with no other applications elsewhere in the hydrocarbon extraction process) are not assigned a colour banding, but assigned a OCNS grouping, A – E based on the PBT data.
Group A- products are considered to have the greatest hazard potential and Group E the least (see Tables 2 and 3 below).
The OCNS grouping
During the hazard assessment process, each individual substance is ranked by applying the OCNS ranking scheme. The overall ranking for a product is determined by the product substance which has the worst case OCNS ranking. The method of assignment of the OCNS letter grouping is described below.
The initial group is determined using Table 2. All submitted toxicity data for each substance is compared against the table. The most toxic response is used as the initial Group for the substance.
Table 2: Initial OCNS grouping
Result for aquatic-toxicity data (ppm)
Result for sediment-toxicity data (ppm)
- Aquatic toxicity refers to the Algae EC50, Crustacean LC50, and Fish LC50 toxicity tests (units = ppm or mg/kg)
- Sediment toxicity refers to the Sediment re-worker LC50 test (units = ppm or mg/kg)
Adjustment of final OCNS group
The final grouping is determined using Table 3 as a guide.
Select the column that applies to the candidate substance and adjust the initial Group accordingly. If the classification should theoretically move beyond Group A or E, the product will be assigned to that Group.
Table 3: Adjustment criteria for OCNS grouping
|Increase by 2 groups (e.g. from C to E)
|Increase by 1 group (e.g. from C to D)
|Do not adjust initial grouping
|Decrease by 1 group (e.g. from C to B)
|Decrease by 2 groups (e.g. from C to A)
|Substance is readily biodegradable and is non-bioaccumulative
|Substance is inherently biodegradable and is non-bioaccumulative
|Substance is not biodegradable and is non-bioaccumulative
|Substance is inherently biodegradable and bioaccumulates
|Substance does not biodegrade and bioaccumulates
|Substance is readily biodegradable and bioaccumulates
The Definitions of the terms are:
- Readily biodegradable: results of >60% biodegradation in 28 days (OECD 306,301B -F method), >70% in28 days (OECD 301A, 301E) to an OSPAR HOCNF accepted ready biodegradation protocols
- Inherently biodegradable: results of >20% and <60% (<70%) to an OSPAR HOCNF accepted ready biodegradation protocol.
- Not biodegradable: results from OSPAR HOCNF accepted ready biodegradation protocol or inherent biodegradation protocol are <20%, or half-life values derived from aquatic simulation tests indicate persistence
- Non-bioaccumulative: Log Pow <3, or BCF ≤100, the molecular weight is ≥700
- Bioaccumulative: Log Pow ≥3, or BCF >100, the molecular weight is <700, or if the conclusion of a weight-of-evidence expert judgement under OSPAR Agreement 2008-5 is negative
In the above section, it has been explained how hazard assessment of an offshore chemical is conducted, based on the test data provided by the chemical supplier on the HOCNF. However, the reproducibility of the tests involved is imperfect.
To provide the most accurate pre-screening of the chemicals submitted for assessment, Cefas therefore takes account of the data it holds for similar substances. This is known as The Global Approach, which is based on the Weight of Evidence principles described by ECHA Practical Guide 2: How to Report Weight of Evidence and in Sections R.4 and R.7a-R.7c of the Guidance on
Information Requirements and Chemical Safety Assessment provided under REACH legislation.
Where multiple biodegradation screening test results of equivalent quality exist, a positive result is accepted over negative results. This application of the global approach may result in the removal of a substitution warning.
Where there are less than 3 values for the same endpoint and they are within 1 order of magnitude the lowest value will take precedence. Where there are greater than 3 values for the same endpoint and they are within 1 order of magnitude the geometric mean will be calculated and used in the assessment
Bioaccumulation (BCF Tests):
A BCF value will take precedence over any other data and will be compared to HMCS criteria. Where more than one BCF value occurs, the highest value will take precedence.
Consideration of global BCF data could remove or apply a substitution warning based partly on Log Pow data, since BCF data always takes precedence over Log Pow data.
Bioaccumulation (Log Pow):
Where only Log Pow data are available and there are less than 3 values the highest value will take precedence. Where there are greater than 3 values the geometric mean will be calculated and used in the assessment. The relevance of WOE approaches conducted under REACH or HMCS will be evaluated on a case by case basis.
It is stressed that the applicability of the Global Approach is only valid where the data being compared relate to the same substance. Expert judgement is used to ensure that this is the case, assisted by database searches and discussions with suppliers, where required.
References: OSPAR Agreement 2012-05, paragraphs 10-12.