In the recent era, there has been a graphic increase in the use of chemicals in each and every sect. many of them previously thought to be benign or harmless in humans, have been found to be carcinogenic or toxic to the reproductive process.  To identify and estimate the true risks, highly effective and comprehensively applicable “Chemical Risk Assessment Structure” should be defined.


Potential Effects Of Exposure To Chemicals

  • Acute toxicity Irritation 
  • Corrosiveness 
  • Sensitization toxicity
  • Mutagenicity 
  • Carcinogenicity
  • Toxicity for reproduction



Chemical Risk Assessment 

 This is a scientific attempt to identify and summing up the true risk, following potential toxic effects by each of the probable routes of exposure – by ingestion, by absorption through the skin and inhalation. It might have an inversive effect on both involved workers and the general public, and of those potentially exposed to them.

While carrying out a risk assessment, the assessment team would divide its total work into its unit wise activities and assess each work practices separately.

With comprehensively used commercial chemicals there is usually detailed database of their toxicological properties on product labels and datasheets. This information is an important source of hazard estimation and has been used to classify many chemical according to the type and potency of the hazard.



Areas those should be considered severally are:

  • Activities such as maintenance, hazardous wastes management, and workforce that may be in the working area.
  • Possibility of accidental injection or ingestion and Their adverse effects.
  • Biological effects of toxic chemical’s intake, from the presence of pathological micro-organisms.
  •  Internal radiation following ingestion or external radiation if handled or near-by.
  • Obvious dangers associated with explosive or flammable substances.


Process Of Chemical Risk Assessment Structure

  • Divide Up The Workplace

If you’re workplace is too large to be assessed, begin your risk assessment by segmenting it up into smaller sections such as

  • Locations

 Physical Work Zones:

  • administration building
  •  laboratory
  •  raw materials intake and storage
  • weighbridge and site entry points 
  • warehouse for packing, storage, and distribution
  • production area with bulk distribution points
  • maintenance workshop and spare parts/supplies stores



  1. b) Working Groups

To conduct chemical risk assessments within similar work groups would be especially useful for:

  • Cleaning and maintenance staff whose work takes them into close contact with various chemicals
  • Workgroups who have to move in different areas in to shifts.
  • Seasonal, remote, and offshore workers
  • Workers using known carcinogens or other substances that require regular health inspections.


  1. c) Chemical Groups

Risk assessments can also be conducted according to chemicals groups

  • Risk / Hazard categories(eg, flammable liquids, compressed gasesexplosivestoxic substances)
  • Usage (eg, spray paints, solvents, glues and adhesives, pesticides)
  • Storage and Handling (eg, bulk stores, package stores, decanting stations)

 2) Examine Work Practices And Conditions

After segmented the workplace, consult with the workers, contractors, staff and supervisors. Collect a full list of substances and the instructions of their use. This process also involves observing staff on the job and speaking with supervisors.


  • Assessing Various Reports

Take an expansive look by examining incident, accident, and sick leave reports that may help you to get information about chemical spills, fires, illnesses, injuries, and near misses. 

  • Sick leave records can indicate a chemical accident, fire or exposure that was never officially reported.
  • Safety meeting minutes can expose a chemical hazard reported by a worker but never followed up.
  • Supplier invoices with out-of-sequence purchases of chemicals, first aid supplies, or fire protection equipment can indicate unreported chemical spills or accidental releases.
  • Recurring accidents involving the same employee (or the same department) can indicate training inadequacies or slack supervisors.


Steps For Chemical Risk Assessment Structure 

Chemical risk assessment is divided into nine steps.


Step # 1:

Gathering Data On The Types Of Hazards

  • Human Health Effects: 

The health effects include congenital, neurological, mutagenic, endocrine disruption and carcinogenic effects. Behavior of the chemical within the body and interactions with organs, cells, or genetic material. 


  • Environmental Damage:

 The environmental damage is lethal effects and sub-lethal effects on growth and reproduction of various populations.

To mark off the potential hazards posed by toxic chemicals, various sets and sub sets of toxicity tests have been devised. Results from these tests provide useful information to forecast effects in natural ecosystems.



Step #2:

Relation Between Concentration Of The Dose And Responses


In this step, the relation between concentration of the dose and responses (probability of harm) of the organism is defined. The relation can be found by laboratory examination or by estimation methods from scientific libraries or via online data searches.

Based upon this research, a most probable level of no effect (NEL) is assessed. 


Step #3:

Uncertainty Of Safety Factors


The uncertainty of safety factors that reflects the amount of uncertainty should be seriously considered when experimental laboratory data or estimation is extrapolated to existing conditions.

 Usually, safety factors of 10–1000 are used. 

If complete information of the chemical is available, then a safety factor of 10 may be applied. 

If the available information has a very high uncertainty, then a safety factor of 10,000 may be applied.

NEL times (no effect) the safety factor is the ‘predicted no effect level’ (PNEL). The complexity is often simplified by deriving the predicted no-effect concentration (PNEC) for different environmental components (water, soil, air, biotas, and sediment).


Step # 4:

Assessment Of Emission In The Surrounding


 This step is of an assessment of how much of the chemical is wasted in the environment by production and use and the sources and quantities of emissions. The assessment requires extensive knowledge of the production and use of the chemical compounds. The chemical may also be a waste product, which makes it very difficult to determine the amounts involved. 

Step # 5:

Development Of An Environmental, Eco toxicological Model


The actual exposure concentration can be assessed by comparing model results with frequent measurements of environmental concentrations. 

The use of models is necessary when we are considering a new chemical, or the assessment requires a very large number of measurements to determine the variations in environmental concentrations.



To develop a model and to make at least a few measurements of concentrations in the ecosystem components, implicit parameters, describing the properties of the chemicals and the organisms is required.

 The development of an environmental, Eco toxicological model also requires a wide range of estimation methods. Extensive knowledge of the physical-chemical-biological properties of the chemical compound(s) should also be considered. 

Step # 6:

Risk Quotient: Ratio PEC/PNEC



The ratio PEC (Predicted Environmental Concentration) / PNEC (Predicted No Effect Environmental Concentration) usually calculated for a wide range of ecosystems. It should be considered an absolute assessment of a relative ranking of risks.


Step # 7:

Chemical Risk Valuation


To decide measures for risk reductions, risk valuation is the most essential activity.

Chemical risk can be classified in two levels:

  1. The upper limit, that is, the maximum permissible level (MPL).

(2) The lower limit, that is, the negligible level (NL). 

             The two risks limits help to decide various risk zones:

  • Black Zone: unacceptable, high risk zone >MPL
  • Grey Zone : medium risk level
  • White Zone: low risk level <NL.



Step # 8:

Relation Between Chemical Risk Assessment Structure And Benefit

Chemicals risk assessment has environmental, social, economic, political, and technical benefits

(1) Improvement in cost efficiency

 (2) Modifications in resource efficiency

 (3) Safe trade and industry operations

 (4)  Progress in workforce health

 (5) Resolve environmental protection issues

 (6) Ready to compliance with international obligations and commitments

 (7) Cooperate to sustainable national development


Step # 9:

Reduction Of Chemical Risk

The risk be reduced to an acceptable level by undertaking deep technical, economic, and legislative investigation.

 Important aspects for risk reduction in ‘Chemical Risk Assessment Structure’ are:

  1. Elimination: Avoid the use of the hazardous chemical.
  2. Substitution: Replace the hazardous chemical with a less hazardous substance.
  3. Controls: Isolate people from the hazardous substance.
  4. Administrative controls: Change working practices.
  5. PPE: Encourage people to use personal protective equipment.


Final Vestige Of ‘Chemical Risk Assessment Structure’ 

Finally a method statement that explain how you will carry out the assessment: 

  • Arrive at site.
  • check in with venue host.
  • Move equipment to be set-up to allocated area.
  • Unload equipment in line with risk assessment.
  • Make sure vehicle is moved to a designated area.
  •  Set-up structures following agreed method statement as manufacturer’s instructions.
  •  Maintain safety controls throughout the day’s activities. 

And at end of the day,

  • Pack away all items brought on-site in line with risk assessment.


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Tag: Health & Safety   Health & Safety Training

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