Chemical Safety Report (CSR)

 

Risk Assessment of Chemicals

Chemical Safety Reports are the main end point for data assessment under REACH in which hazard and exposure data are considered together to assess the risk of a substance. 

 

Introduction to risk assessment

 

A risk assessment is the result of combining a hazard assessment with exposure scenarios – risk is a function of hazard and exposure.  To put it very simply:

 

Non-hazardous and low exposure = low risk

Non-hazardous and high exposure = good hazard assessment required

Hazardous and low exposure = risk management required

 

A hazard assessment needs to consider the physico-chemical, toxicological and ecological properties of a chemical substance and the result of this assessment leads to Classification with assignment of ‘H Statements’; however, this does not reflect the risk of the materials to workers, consumers or the environment and to take the hazard data to the next stage of assessment, it is necessary to understand potential exposure.

 

Risk assessment principles

REACH requires information on exposure to be gathered for all registered substances. For substances in the 1-10 tonnage band, this is a simplified set of information. For all substances manufactured or imported in quantities of 10 tonnes per year or more, a formal Chemical Sagety Report (CSR) must be produced.

 

Even without the need to meet regulatory requirements, ‘risk assessment’ is an essential part of responsible care during the production, supply or use of any chemical material.  A basic risk assessment will help determine what conditions to avoid or what protective equipment to recommend to meet statutory requirements for handling chemicals – such as the communication or risk to customers, protection of workers and also to minimum impact on the environment through loss or accident.  The Safety Data Sheet (SDS) itself is a product of a risk assessment in that it describes how to reduce exposure in accordance with known properties of the material. Under REACH, the SDS needs to take into account elements of the CSR.

 

Any type of risk assessment should include consideration of:

 

·         The life cycle of the product

·         Potential hazards to health and the environment

·         Physical form (solid, powder, liquid, gas etc)

·         How is the product handled (manually, automatically)

·         Is there contact with workers / consumers

·         Is there a chance of loss to the environment

·         What happens to the product after use (disposal)

 

The conclusion of a risk assessment is to compare the estimated exposure with the estimated effects to derive a risk characterisation ratio (RCR); for the environment, this is expressed as a PEC / PNEC - the ratio of predicted environmental concentration (PEC) over predicted no effect level (PNEC).  Human health elements to the risk assessment are less clear-cut in their conclusions, but the principles remain the same with a comparison between the predicted level of exposure and the Derived No-Effect Level (DNEL), which is estimated from toxicity data with the application of safety factors.

 

The environment

The Predicted Environmental Concentration (PEC) is based on models for the degradation or distribution of the substance in the environment (between water, air and solids) using physico-chemical and biodegradation data.  As well as the test data, other key factors include how the substance is manufactured, formulated or used and the dilution factors from use. 

 

The distribution of chemicals discharged to waste water treatment plants is described in the aptly named ‘SimpleTreat’ model.  This is a simplistic model that considers the volatility (Henry’s constant, H), the partition coefficient, adsorption coefficient and biodegradation.

 

Volatility

Log H > 3

= Significant loss to air

Partition coefficient

Log Kow > 3

= Accumulation threat

Adsorption Coefficient

Log Koc > 3

= Adsorption to soil / sediment

Biodegradation

> 60%

= Biodegradable

 

The model, presented in tabular form in the TGD or incorporated into the software of the risk assessment model EUSES (see below), compares each of these factors in determining the distribution of the substance in the environment.  A water soluble substance with Kow = 0, that is biodegradable, for example, is predicted to be 76% degraded with 24% lost to surface water.  But a non-biodegradable poorly water soluble material with a Log Kow of 4, may have 56% to water and 44% to sewage sludge.

 

Default figures are provided in the Technical Guidance Documents (TGD) for Directive 93/67/EEC, describing estimated concentrations of waste in effluent, standard dilution factors, sizes of water treatment plants etc. These default values consider worse-case scenarios with, for example, 2% of material produced being lost to waste water, the position of the production unit in a small town with a small treatment works, and with final discharge going into a small stream. However, where only limited sites are involved in production, formulation or use, location-specific factors can be used, such as the size of the waste treatment works, river flow rates etc.  and this can make a big difference to the final conclusion.

 

The Predicted No Effect Concentration (PNEC) is based on environmental effect data, such as toxicity to fish, Daphnia or algae and is determined by applying a safety factor. For acute studies, the safety factor of 1000 is applied to the EC50 value; ie. a Daphnia EC50 following 48 hours exposure of 50 mg/l would lead to a PNEC of 0.05 mg/l.  Longer-term studies require a smaller safety factor, as indicated below; 

 

Acute EC50

÷ 1000

(Acute = short term, eg 4 days fish)

Sub-acute EC50

÷   100

(Sub-acute = medium term, eg 21 days fish)

Chronic EC50

÷    10

(Chronic = long term, pond work etc)

 

 

 

In the absence of effects with acute studies, the PNEC is set at 1/1000 of the limit of solubility; likewise if there are no effects in longer-term studies, the PNEC will be 1/100 or even 1/10 of water solubility.

 

The ratio between PEC and PNEC is ultimately used as an indicator of risk, allowing it to be quantitatively labelled. For REACH the aim is to achieve a RCR of less than 1, i.e. exposure levels less than the PNEC.  If the PEC is greater than the PNEC (ie. ratio > 1 ), then it can be assumed that there is a risk of effects to the environment.  The scale of the risk can therefore be crudely measured by considering this ratio – a figure of 1 to 10 is of low concern, but over 100 is of major concern, and limitation of supply could be required. 

 

Human exposure

A risk assessment based on human exposure should consider the type of exposure; whether deliberate or accidental, whether repeat or one-off or whether direct (eg. factory workers) or indirect (eg. in food or drinking water).   The physico chemical properties such as dusts, vapours or liquid inhalation, splashing must also be considered as this can effect exposure routes.  Physical hazards, such as flammability or explosivity are also important for overall risk considerations. 

 

Quantifying exposure is very difficult and models attempting to make this easier (such as the EU model, EASE) rely on inputs such as vapour pressure, temperature of the process leading to exposure, dust content etc.  Other than the rather simplistic model EASE, the finer points of human health risk assessments should be left in the hands of an expert.

 

In an attempt to quantify ‘safe’ levels for human exposure, it is necessary to calculate a Derived No-Effect Level (DNEL) that is based on safety factors being applied to toxicity data endpoints such as the lowest observed adverse effect level (LOAEL) or no observed adverse effect level (NOAEL).  The DNEL effectively follows the same principle as the PNEC for environmental effects.

 

Exposure needs to be considered in details in the Exposure Scenario (ES) that is part of the risk assessment process.  The content of the ES is not much more than would currently be provided in a risk assessment for new substances, but is a more formal assessment.  It is also designed to be more specific to particular uses or processes and different processes will require separate ES.

 

It is necessary to make a full review of all parts of the life-cycle in which the substance can come into contact with people, including manufacture, transport, storage, formulation, use and disposal.  Parts of the life cycle may not be obvious, such as the exposure to pigments caused by the degradation of paints.  The exposure during manufacture of a pigment or its formulation into paint may seem obvious, as is the exposure to the wet paint when applying it to a surface.  However, the exposure to the paint from weathered surfaces is less obvious, but it all needs considering.

 

REACH introduces the concept of the ‘Derived No Effect Level’ (DNEL) that tries to quantify the no effect concentration for human exposure.  This is more complex than the Environmental PNEC (see above in that it considers inter-species reliability as well as the end-points assessed.

 

Default assessment factors taken from REACH Guidance on Information Requirements, Table R. 8-6

 

Assessment factor – accounting for differences in:

Default value systemic effects

Default value local effects

Interspecies

-          correction for differences in metabolic rate per body weight

-          remaining differences

 

AS a, b

 

2.5

 

1 f

2.5 g

Intraspecies

-          worker

5

5

-          general population

10 c

10 c

Exposure duration

-          subacute to sub-chronic

3

3 h

-          chronic to chronic

2

2 h

-          subacute to chronic

6

6 h

Dose-response

-          issues related to reliability of the dose-response, incl. LOAEL/NAEL extrapolation and severity of effect

1 d

1 d

Quality of whole database

-          issues related to completeness and consistency of the available data

-          issues related to reliability of the alternative data

1 d

 

 

1 e

1d

 

 

1e

 

a              AS = factor for allometric scaling (see Table R. 8-3)

b             Caution should be taken when the starting point is an inhalation or diet study

c              Not always covering for very young children; see text for deviations from default

d             See text for deviations from default

e             Special consideration needed on a case-by-case basis

f              for effects on skin, eye and GI tract via simple destruction of membranes

g              for effects on skin, eye and GI tract via local metabolism; for effects on respiratory tract

h             for effects on respiratory tract.

 

 

 

Risk assessment software

To help users of chemicals, software can be obtained from European Competent Authorities (such as the UK HSE).  Programs include ECETOC TRA and EASE for making a simple assessment of worker exposure and EUSES for predicting environmental impact. 

 

EUSES is quite complex to use and interpret and can be manipulated to give a more realistic answer than if it is used at its most basic level, using pre-set defaults.  For example, simple changes can be made to change the size of waste water treatment works or to put in the correct local dilution rate when effluent finally reaches surface water in the environment.  It is also possible to make changes to more subtle parameters that only environmental chemists can fully understand – or at least, they claim to be able to.

 

More recently, ECHA have released a new tool. CHESAR that brings together the models EUSES and ECETOC TRA.

 

Communicating Risk

The communication of risk to customers is through the SDS and where appropriate, the Exposure Scenario.   Even though substances over 1 tonne supply will need to be considered with an exposure scenario, lower volume hazardous substances will still require an SDS in the same way as currently applies.

 

The CSR does not need to be given to customers, but the ‘enhanced’ SDS must take into account the conclusions in considering risk reduction recommendations. 

 

Preparing a CSR

The CSR should be prepared using the templates provided by ECHA. The CSR consists of two parts; Part A is the conclusions and declarations that risk management measures are implemented and communicated and Part B that is the main technical component.

 

 

Part B covers:

 

  1. Identity
  2. Manufacture and use patterns
  3. Classification and labelling
  4. Environmental fate assessment
  5. Health hazard assessment
  6. Physical hazard assessment
  7. Environmental hazard assessment
  8. Assessment of whether PBT or vPvB
  9. Exposure assessment
  10. Risk characterisation

 

The main source of hazard data will be the Chemical Safety Assessment (CSA) and the format for this will consider the environmental hazard, the human health hazard and physico-chemical health hazard data as well as the vPvB potential.  If vPvB, additional elements will need to consider exposure assessments and risk characterisation; if vPvB, close control over supply is expected and it is possible that Authorisation will not be given.

 

Exposure Scenario (ES)

The CSA needs to be considered in the light of the ES and the resulting comparison will provide the key to the risk assessment – comparing hazard and exposure.

 

To prepare the ES, suppliers will need to liaise closely with their customers to ensure that the scenario for exposure is realistic and conversely, once prepared, the user must not deviate from conditions used for the ES.  For specialist uses, or if the use is considered confidential, the user will need to prepare an ES and perhaps even a new CSR to cover their particular use.

 

The communication of exposure data up and down the supply line is anticipated to be one of the more difficult activities facing industry.  There are perceived to be many problems concerning confidentiality and data ownership, but only industry can find answers to the communication problems.  Downstream users (DUs) can provide their own ES and CSR, but will need to report to the European Central Agency these uses in case the Registration of the substance is itself compromised and new Authorisation is required.

 

Technical Guidance Documents

Comprehensive Guidance on Information Requirements and Chemical Safety Assessment is available from ECHA.

 

SDS Communication

The format of the SDS has been updated under REACH to include the findings of the ES and CSR. These findings need to be communicated in various section of the SDS and it is important that the risk reduction recommendations are consistent with the ES and CSR. 

 

The ES may also need to be supplied to the customer to provide more detailed information on safe handling and control.  Sections relating to physico-chemical properties, toxicology and ecotoxicology must also be consistent with the CSA that in turn has been used to prepare the CSR.

 

Effectively, the job of the SDS remains the same, but under REACH, it is expected that there will more information to communicate at a greater level.  Chemical supply may also be linked to specific uses only and the SDS must obviously make this clear.

 

For the vast majority of non-hazardous products, there may be little real change in communication requirements.

 

Control and Authorisation

Dangerous substances may be Restricted through Annex XVII of REACH, or Authorised only for specific uses that have been considered to represent an acceptable level of risk or are considered to be of socio-economic benefit for a specific function.  Restrictions and Authorisation can be expected on substance considered to be CMR (Carcinogenic, Mutagenic or Toxic for Reproduction) or that are PBT or vPvB.  

 

For all hazardous substances, some level of risk management will be required and this is to be proposed in the CSR and communicated through the SDS and ES.

 

Conclusions

Good risk management of all chemicals is reliant on good communication – by informing those in contact with or responsible for the use of chemical of hazards and then proposing mechanisms for control of exposure, risk reduction is possible.  Exposure control must be proposed to reflect the hazard and good communication will allow judgement to be made on the level of control required. 

 

Denehurst Chemical Safety Ltd