Synchronising in the right way Chesar with IUCLID is fundamental to have the full alignment between the use description in IUCLID and the exposure scenarios in the CSR when using Chesar. To have the same use description in IUCLID and in the exposure scenarios in the CSR when using Chesar, we recommend starting by describing the uses in Chesar.

Once all your uses have been assessed in Chesar, they can be transferred into IUCLID using the export function in Box 4 by selecting the option Remove all existing uses. This option will:

• Transfer (or update if already existing) into IUCLID section 3.5.all uses reported in Chesar
• Remove the existing use (if any) in IUCLID

Remember that you should always export again the uses to IUCLID whenever have updated your use description and/or your assessment Chesar by using the same "Remove all existing uses" option. Only by doing this, you will ensure that your use description in IUCLID and the exposure scenarios in the CSR remain aligned and you would avoid failing the CSR technical completeness check that ECHA performs in the REACH registration dossiers.

If in your section 3.5 of IUCLID you have additional uses that are not to be assessed in Chesar see the FAQ “How should I report uses/contributing activities that do not require an exposure assessment in Chesar” and “I synchronised the Chesar uses in IUCLID. How and where should I add a use as intermediate in strictly controlled condition that do not need to be assessed in Chesar?”. 

If you are a lead registrant and have uses that have different type of “related assessment” values (for example both joint and own uses) see FAQ "I am a lead registrant and I need to generate both an own CSR and a joint CSR. How can I use Chesar to ensure that the use description in IUCLID and in the CSR are aligned and consistent with the exposure scenarios?"

If you are a lead registrant and you need to prepare both a joint and an own CSR, you will have to create 2 CSAs in Chesar, one for the joint uses, and the other for your own ones.

Chesar is by default creating “own” CSAs. To flag that the CSA is joint, you need to tick the checkbox “joint” in the CSA editable window in box 1. The only difference between joint/own CSA is the information that will populate the field “related assessment” in IUCLID section 3.5. This IUCLID field indicates if the use is assessed i) in an own CSR, ii) joint CSR or iii) does not need to be assessed. This field is the trigger (used by Chesar and/or IUCLID) to determine whether a use is to be reported in section 2 of the automatically generated CSR.

Once you finalised your joint CSA: in box 4, export your uses by using “Remove all existing uses” (see “How can I ensure the synchronisation of my exposure scenarios in the CSR generated by Chesar with the use description in IUCLID? Which option shall I choose in Box 4 of Chesar?"). IUCLID will then only contain uses flagged as “joint use” in the “related assessment” field.

Proceed to the “full CSR generation” from Chesar box 4 to generate your joint CSR (and related part A). Contextually, Chesar will also create a new record in IUCLID section 13, documenting the required information fields and including the Joint CSR document.

Note that in IUCLID “related assessment” field there is also the option “use assessed in a joint CSR but not a lead’s own use”, that may be used by the leads to clarify in the CSR that one or more uses are not to be considered his own use, although assessed as part of the joint CSR.

Then proceed with your own CSA: after finalising it in Chesar, export your own uses by selecting the option “Remove all uses from IUCLID identified as "use assessed in an own CSR" in the field "Related assessment" and which have not been previously exported from Chesar” (see FAQ 1 for more details). By selecting this option, you will keep the previously exported joint uses and have a complete use description in IUCLID (covering both joint and own uses). Then proceed with the generation of your “own” CSR from Chesar box 4 (with the related part A); also in this case, Chesar will create a new record in IUCLID section 13, including your “own” CSR document.

A good practice is always to check the content of the generated CSR and ensure that the information contained is reflecting your actual situation.

In case an exposure assessment is not required for a specific use, for example, because the concentration of the substance in the product/mixture used is below the threshold described in article 14 (2) then it is suggested to document this information in the following way in Chesar 3

• create the corresponding use in the life cycle tree and assign a clear and descriptive name to the use
• provide the justification for the absence of the exposure assessment in the “Further description of the use” field. More information on the content of justifications can be found in section 4 of "Information on manual verification at completeness check "
• provide information that is required in IUCLID section 3.5 to make a technically complete dossier (e.g., technical function of the substance during use)
• create the corresponding contributing activities (to make a technically complete dossier when exporting your uses from Chesar to IUCLID)
• export your uses from Chesar into IUCLID

In case the exposure assessment is not required for a specific contributing scenario within one use, for example, direct exposure of consumers due to use of cosmetic products, it is suggested to document this information in the following way in Chesar 3:

• create the corresponding use in the life cycle tree and assign a clear and descriptive name to the use
• provide information that is required in IUCLID section 3.5 to make a technically complete dossier
• create the corresponding contributing activity
• provide the justification for the absence of the exposure assessment in the “Explanation for CSR contributing scenario” field
• export your uses from Chesar into IUCLID.

After synchronisation with Chesar, if needed, you may add in IUCLID uses as intermediate in strictly controlled conditions registered under article 17/18 of REACH regulation).

When reporting such uses in IUCLID you should be careful in choosing the picklist “does not need to be assessed” in the “related assessment” IUCLID field. Note that for uses exported from Chesar to IUCLID, this field is always automatically filled-in in IUCLID, based on the selection made in the CSA management tab in Box 1 of Chesar (by default, Chesar sets all new CSA as own CSA ”.

When you need to synchronise again the uses from Chesar to IUCLID, to maintain the uses that have been added in IUCLID only, we recommend choosing the Chesar box 4 option "Remove all uses from IUCLID identified as "use assessed in an own [joint] CSR" in the field "Related assessment" and which have not been previously exported from Chesar".
This option will:

• Transfer (or update if already existing) all uses into IUCLID section 3.5.
• Maintain any previously existing use in IUCLID for which the “related assessment” field is set differently compared to what is set in your Chesar CSA (i.e. if you are exporting uses belonging to an “own” CSA, then all IUCLID uses flagged as “joint” or “use not assessed” or without any selection in the “related assessment field” will be maintained in IUCLID).

We strongly discourage to use the option Update uses that have a corresponding use in Chesar and keep all other existing uses, to avoid creating inconsistency in your IUCLID section 3.5.

When ART is selected as external estimation tool in Chesar 3.6 or newer, after pressing the button “(Re)set relevant default CoU”, the full list of CoU related to the specific ART activity class selected is systematically added. The assessor should review the CoU displayed and, if needed, delete the ones that are not relevant for that scenario. The CoU which should be present in Chesar, should reflect the input used to perform the assessment in ART.

To help users avoid wrong combinations of CoU, it is highly recommended to consult (and apply) the rules indicated in the table below:

Combination of CoU/values that are not compatible when using ART

CoU	Rule
Room ventilation	Not relevant if Place of use = Outdoor
Personal enclosure	Relevant if Distance of workers to the source = ≥1 m
Segregation of the source	Relevant if Distance of workers to the source = ≥1 m
Distance of the source to buildings	Relevant if Place of use = Outdoor
Downward laminar flow booth	Relevant if Room ventilation = Down-flow spray room

Moreover, to ensure a higher level of consistency, the rules indicated in the following second table may be considered when proceeding with an assessment with ART.

Additional rules that ensure consistency when using ART

 

CoU	Rule
Containment	Not relevant if Place of use = Outdoor
Suppression techniques for solid products	Relevant if Physical form of the product = Solid object or solid (all levels of dustiness)
Vapour recovery system	Relevant if Physical form of the product = Liquid, including paste/slurry/suspension

Chesar 3.5 introduces a change in the logic of calculating the workers exposure concentration when assessment entities exist.

The change and its possible consequences on the exposure estimate are described in the FAQ “What is the difference between the calculations of workers exposure when assessment entity exists (parallel assessment) between Chesar 3.5 and previous versions of Chesar?”

This change has been introduced after analysing feedback received from Chesar users. For substances assessed via the assessment entity approach, the calculation of the workers exposure concentrations in previous versions of Chesar (until Chesar 3.4) was not in line with the principles of ECETOC TRA, leading to an underestimation of the exposure. After a careful investigation, we decided to implement the change in the ECETOC TRA worker module of Chesar 3.5.

Chesar 3.5 is now aligned with exposure modifier approach for concentration as applied in the TRA.

As a consequence of this change, the worker exposure estimate for complex substances done with previous versions of Chesar will change when upgrading to Chesar 3.5. The change may impact on the risk characterisation conclusion. Depending on the extent to which the risk characterisation has changed, you may need to update the operational condition / risk management measures (OC/RMM) for demonstrating control of risk.

As a general information, to obtain ECETOC TRA exposure estimates in Chesar, a number of steps are taken:

• The ECETOC TRA algorithm estimates the “Initial exposure concentration” values based on the substance properties (molecular weight, physical form and vapour pressure) and the PROC selection.
• These initial exposure concentration values are then multiplied with the relevant exposure modifiers in order to obtain the final exposure concentration values. One of these exposure modifiers is the “Concentration of the substance in the product”.

What has changed in Chesar 3.5 is the calculation of this “exposure modifier for concentration” for substances where assessment entities exist.

Until Chesar 3.4, the workflow was the following:

• First, the value from the Chesar condition of use “Percentage (w/w) of substance in mixture/article” (set in the TRA worker dataset) was assigned to one of the concentration bands of the TRA parameter (>25%, 5-25%, 1-5%, <1%).
• The exposure modifier for concentration (for the registered substance as a whole) was then calculated according to the following table:

   

  Concentration	Exposure modifier for concentration
  If Concentration = “Substance not in mixture”	1
  If Concentration = “>25%”	1
  If Concentration = “5-25%”	0.6
  If Concentration = “1-5%”	0.2
  If Concentration = “<1%”	0.1

   

• For complex substances (i.e. when parallel assessment happens), the final exposure estimates returned by TRA workers (where the exposure modifier above has been applied to the registered substance as a whole) were then (linearly) corrected. This correction was made with the percentage of each assessment entity (AE) in the assessment entity group (AEG) (visible in Box 1) used for the assessment, to obtain an exposure estimate for each AE .

In Chesar 3.5, no changes have been introduced in the calculations of the initial exposure concentrations. However, the place in the process where the correction for the percentage of the AE in the AEG takes place has been changed for substances where assessment entities exist.

Once the initial exposure concentrations have been calculated, the following steps are taken:

• First, the percentage of each AE in the AEG used for the assessment is multiplied with the percentage of the substance in the mixture (= the % indicated in the condition of use “Percentage (w/w) of the substance in the mixture/article” at worker contributing activity level) in order to generate the percentage of each AE in the mixture . So the (linear) correction is now done as a first step instead of at the end.
  The resulting percentage of the AE in the mixture is included as read-only in each TRA worker dataset under the TRA specific parameters and called “Percentage (w/w) of <assessment entity name> in mixture/article”.
• This % of AE in mixture is then mapped to one of the concentration bands of the TRA parameter as follows:

   

  Percentage (w/w) of AE in mixture	Concentration
  If % of AE in mixture >= 100	Substance not in mixture
  If 25 < % of AE in mixture < 100	>25%
  If 5 < % of AE in mixture <= 25	5-25%
  If 1 < % of AE in mixture <= 5	1-5%
  If % of AE in mixture <= 1	<1%

   

• The resulting concentration band is then used to determine the “exposure modifier for concentration” according to the following table (no changes from the current implementation).

   

  Concentration	Exposure modifier for concentration
  If Concentration = “Substance not in mixture”	1
  If Concentration = “>25%”	1
  If Concentration = “5-25%”	0.6
  If Concentration = “1-5%”	0.2
  If Concentration = “<1%”	0.1

   

• Finally the “exposure modifier for concentration” is multiplied (together with the other TRA exposure modifiers) with the initial exposure estimates to generate the final exposure estimate for each AE in the AEG.

As a consequence of this change, the worker assessment of complex substances done with previous versions of Chesar will need to be reviewed when updating to Chesar 3.5.

As the conservativeness has been increased, you may be confronted with higher exposure estimates for the assessment entities and for the substance as a whole. The largest impact is expected for assessment entities where the percentage of the assessment entity in the mixture/article is low (i.e. falling in the lowest concentration band in ECETOC TRA) and in cases where the method for calculating the RCR across assessment entities is set to “Summed RCR”. We are aware that in some cases you will now be confronted with RCRs above 1 and that this change may present an assessment challenge. If safe use cannot be demonstrated with ECETOC TRA, the use of other (higher tier) tools which apply a linearized approach to correct for concentration in the mixture/article (as opposed to the banding used in ECETOC TRA) may offer a solution.

When developing Chesar 3.3, ECHA agreed with ECETOC that when a user selects a TRA subcategory the values of the various parameters cannot be modified. The only exception is the percentage of the substance in the mixture/article, which can always be edited. This approach was preferred as

1. it is more consistent with the SCED approach and
2. it allows for a more transparent reference to a TRA subcategory with a set of default values proposed by ECETOC.

If assessors want to use different values as input in Chesar, they should switch to a manual assessment. In Chesar 3.3, when switching from “TRA subcategory” to “manual assessment” while working with a TRA subcategory, the link to the TRA subcategory is lost. However, if needed, you may refer to it in your explanation for CSR for some conditions of use if you want to justify some “TRA subcategory” values.

When doing this switch, in some cases you may find that your dermal exposure estimates become 10 times higher than what they were when you used the subcategory. This difference is the result of the agreement mentioned above and only affects the following TRA subcategories:

• PC3, Aircare continuous action (solid & liquid)
• AC5/ AC5g, Bedding, mattress
• AC6, Purse, wallet, covering steering wheel (car)
• AC6/ AC6f, Footwear (shoes, boots)
• AC6/ AC6e, Furniture (sofa)
• AC8/ AC8f2, Printed paper (papers, magazines, books)
• AC10/ AC10e/ AC10g, Rubber handles, tyres
• AC10/ AC10a, Flooring
• AC10/ AC10f, Footwear (shoes, boots)
• AC10/ AC10b, Rubber toys
• AC11/ AC11e, Furniture (chair)
• AC11/ AC11a, Walls and flooring (also applicable to non-wood materials)
• AC11/ AC11b, Small toys (car, train)
• AC11/ AC11f, Toys, outdoor equipment
• AC13/ AC13a/ AC13e/ AC13g, Plastic, larger articles (plastic chair, PVC-flooring, lawn mower, PC)
• AC13/ AC13b, Toys (doll, car, animals, teething rings)
• AC13/ AC13f, Plastic, small articles (ball pen, mobile phone)

This difference is caused by a TRA parameter not visible in Chesar called Thickness of Layer (TL), which is not modifiable (neither in Chesar nor in TRA). For dermal exposure assessment of mixtures the TRA tool assumes that a layer (TL) of 0.01 cm of a mixture interacts with the skin, and the substance amount contained in this layer is, by default, immediately and completely transferred to the skin (i.e. dermal transfer factor set to 1). For the TRA subcategories mentioned above, this concept is also applied, but a reduced thickness of layer of 0.001 cm has been set to account for the reduced mobility of substances in the article matrix. When switching from one of these TRA subcategories to a manual assessment, the TL is automatically changed from 0.001 cm to the default 0.01 cm, and this is what causes the estimates to become 10 times higher. Depending on how your manually assessed use-scenario differs from that covered in the TRA subcategory, you may conclude that the TL of 0.001 is still more appropriate for your case than the default of 0.01.

Bear in mind that you may encounter this issue also when migrating from Chesar 3.2 to Chesar 3.3. In Chesar 3.2 it was possible to change some of the default values when a subcategory was selected (as is the case in ECETOC TRA). In case you had modified any of the editable parameters (e.g. amount of product used per application, body parts potentially exposed etc.) in Chesar 3.2, a switch to “manual assessment” takes place during migration to Chesar 3.3. As a consequence, there is no longer a reference to the subcategory and, if you used one of the TRA subcategories listed above, the TL is set to 0.01, and the dermal exposure estimate is 10 times higher than the value provided in Chesar 3.2.

The ESCom phrase catalogue supports the IT exchange of ES information via ESComXML and the harmonisation of communication downstream in the supply chain. If translations of the ESCom phrase catalogue are available, the exposure scenarios to be communicated in the extended SDS can be automatically generated in various languages.

More information on the ESCom package as well as the latest version of the ESCom standard phrase catalogue in Chesar format can be found here.

No, in Chesar you can use either a standard phrase or free text. A combination of the two is not allowed.

Registrants will be able to find use maps generated by downstream user sector organisations in Chesar format (when available) on http://echa.europa.eu/csr-es-roadmap/use-maps.­ Use maps are developed by sector organisations and are only hosted by ECHA in a centralised place.

All the fields describing the uses and contributing activities are imported into IUCLID section 3.5 once you click the “Export uses to IUCLID” button in Chesar Box 4. More specifically, all conditions of use, releases and exposure estimates will populate the related fields in the contributing scenarios tabs (for environment, workers and consumers) in IUCLID section 3.5. Additionally, information on environmental assessment from aggregated sources will populate the related fields in IUCLID section 3.7. If information on use description is added or modified once the uses from Chesar have been exported to IUCLID, the information in IUCLID will be overwritten when the uses are exported again.

When ECETOC TRA is used for the exposure assessment at an elevated operating temperature (>40°C), for liquid the tool automatically selects the higher volatility band to perform the calculations. You can manually adjust the vapour pressure at the relevant (elevated) temperature by overwriting the value under the “TRA specific parameters” section in the TRA edit view in Chesar Box 3.

Chesar 3 has EUSES (for environment) and ECETOC TRA (for workers, consumers) plugged in for exposure estimation.

• EUSES supports the assessment of solid substances, as soon as basic substance properties (Molecular weight, melting point, solubility, vapour pressure, partition coefficient octanol water and biodegradation screening tests) are provided. Therefore, even for solid substances, a vapour pressure must be provided to obtain EUSES exposure estimates.
• TRA consumers does not have specific limitations for solid substances.
• TRA workers supports the exposure assessment of solid as such or in solid mixture. The exposure estimates are calculated based on the level of dustiness of the product used. Chesar 3.3 supports the exposure assessment of solids in liquid mixtures. For more information refer to “Targeted Risk Assessment: Further Explanation of the Technical Basis of the TRA v.3.1 - Technical Report No. 131", ECETOC, 2018

When the operating temperature is below the melting point for a solid substance, the substance is considered as solid and the provision of TRA workers 3.0 for solid substances are applied (exposure estimates are calculated based on the level of dustiness of the substance). If the operating temperature is above the melting point, the substance is considered in Chesar as liquid, and TRA workers 3.0 for liquid is applied for exposure estimation, which means that the exposure is a function of the vapour pressure.

No. However, you can report the relevant information in Chesar Box 4 in the “Workers combined risks” field in section 10.1.

Chesar 3 has the possibility ­­to assess “complex substances” such as substances with many constituents (including UVCBs) and substances which transform by the use of Assessment Entity Groups (AEG). The prerequisite is to create assessment entities in section 0.4 of IUCLID 6 (you can find more information in IUCLID manual for registration https://echa.europa.eu/documents/10162/22308542/manual_regis_and_ppord_en.pdf).

These will be imported with your substance properties data in Chesar through the web service. The assessment entities can then be used to create AEG which can be used for the assessment. For more information on how to define the AEG refer to Chesar help text in Chesar Box 1. You may also get more information in part D of the Guidance on Chemical safety assessment https://echa.europa.eu/documents/10162/13632/information_requirements_part_d_en.pdf.

ECETOC TRA workers 3.0 does not provide exposure estimations for PROC 28. However, in some cases, the exposure potential during maintenance is similar to the exposure potential occurring during other types of activities. In such cases, if a suitable justification is reported, the exposure estimation can be based on a different PROC (e.g. PROC 8a when there is a potential for a direct contact with the substance) and in Chesar, the following procedure can be applied:

1. In Box 2, create a worker contributing activity and assign e.g. PROC 8a.
2. Carry out your exposure assessment in Box 3 by adding a TRA workers 3.0 exposure dataset.
3. Specify your set of conditions of use.
4. Add an external tool exposure dataset. In the “external tool exposure dataset” view, link the conditions of use already specified for the TRA assessment, copy the exposure estimates obtained with TRA and justify your selection of PROC (e.g. PROC 8a) for the exposure estimates in the “explanation on exposure estimations” field.
5. When the information from the TRA assessment has been copied into the external tool dataset, the TRA workers 3.0 exposure dataset can be deleted.
6. Go back to the contributing activity level in Box 2 and overwrite the PROC used for the assessment (e.g. PROC 8a) with PROC 28.

Some contributing activities at end-use of chemicals may take place in closed conditions similar to those in the chemical production and refineries, and therefore TRA exposure estimates for PROC 1-3 could be applicable. It should be noted nevertheless that in sectors other than chemical production and refineries a measured data set is needed to validate the use of a “PROCs 1-3 based assessment” (see Guidance R14). With this basis, a similar technique as described for the aforementioned question can be applied.

1. Create a worker contributing activity to which the PROC describing closed systems (e.g. PROC 2) is assigned.
2. Carry out your exposure assessment in Box 3 by adding a TRA workers 3.0 exposure dataset.
3. Specify your set of conditions of use.
4. Add an external tool exposure dataset.
5. In the “external tool exposure dataset” view, link the conditions of use already specified for the TRA assessment, copy the exposure estimates obtained with TRA and justify your selection of PROC 2 for the exposure estimates in the “explanation on exposure estimations” field.
6. When the information from the TRA assessment has been copied into the external tool dataset, the TRA workers 3.0 exposure dataset can be deleted.
7. Go back to the contributing activity level in Box 2 and overwrite the PROC used for the estimation (e.g. PROC 2) with the PROC characterising the nature of the activity carried out under closed conditions.­
8. Do not forget to add the measured dataset (as supportive exposure assessment) which justifies the claim of closed system for the activity

In Chesar some key information related to the waste stage can be documented for each contributing activity for the environment, such as the fraction of substance released to waste stage and whether particular considerations have to be taken into account for the waste treatment operations. There is no particular functionalities for assessing the waste life stage of a substance in Chesar. Nevertheless, it is possible to assess the treatment of waste as a “use” at industrial site.