Interpreting commonly used regulatory and chemical initialisms


What is the STEL for that vPvB SVHC?

To the layperson that sentence probably looks unintelligible. Perhaps there are a few vowels missing? In the world of chemical regulations, however, it makes perfect sense. 

If you’re feeling a little overwhelmed by all the acronyms and initialisms used in the chemical regulation industry, we are here to help! In this article, we make a start by interpreting and explaining five of the most commonly used initialisms—from TWA to SVHC. 

TWA, STEL and C: Exposure Limits 

The first three initialisms we’re unpacking here are used to describe exposure limits. An exposure limit is the legal or recommended upper or lower limit of time that someone can be exposed to a certain chemical. These are also generally called Occupational Exposure Limits (OELs). The aim of the exposure limit is to mitigate any health or safety risks that come with being exposed to the substance. 

There are different measures of exposure limits depending on the jurisdiction, the type and phase (solid, gas or liquid) of chemical present, and the physical work environment. Exposure limits are measured in mg/m3 or parts per million (ppm). 

OELs have many different names, all meaning the same thing. In the USA, they are called PEL (Permissible Exposure Limits), in Australia, WES (Workplace Exposure Standards) and in the UK, they are called WEL (Workplace Exposure Limits). The three common initialisms related to WES are:

  1. TWA: Time-weighted Average (sometimes called Threshold Limit Value or 8-hr Value)

This exposure limit is calculated over an eight-hour workday or a 40-hour work week. A TWA is the upper limit of the allowable average exposure to a chemical for the period of time mentioned above. This limit is set to ensure no deleterious effects arise from the chemical exposure over a worker’s lifetime.

  1. STEL: Short-term Exposure Limit (sometimes called 15-min Value)

The STEL describes a 15-minute TWA exposure limit. The average exposure over the 15-min period must not exceed the STEL value.

There are three rules for STEL:
a) STEL exposure must not be longer than 15 minutes.

b) STEL exposures must not be repeated more than four times per day.

c) There must be at least 1 hour between successive STEL exposures. 

  1. C: Ceiling Value (sometimes called Peak Value)

This exposure limit should never be exceeded at any time. 

GHS: Globally Harmonised System of Classification of Labelling Chemicals

The GHS was created by the United Nations (UN) in 2002 as a way of co-ordinating chemical classification around the world. Introduced to Australia in 2012, the system provides internationally consistent criteria, labels and names for the chemical classification of health, physical and environmental hazards, which are further classified according to the nine pictograms below. 

The nine pictograms.
The nine pictograms. 

FlammableOxidisingAcute toxicity
Corrosive, eye damageExplosiveIrritant, hazardous to ozone layer, acute toxicity
Environmental toxicitySerious health hazard, e.g. a carcinogenGas under pressure

The standardised system led to an overhaul to Material Safety Data Sheets (MSDS), which are now simply named Safety Data Sheets (SDS). Prior to the introduction of the GHS, the contents and layout of MSDS differed from country to country and even from region to region within countries. The new layout for SDS follows a user-friendly 16-section format that covers information from first aid measures to engineering controls. The GHS also introduced signal words such as “danger” and “warning”, to demonstrate the hazard level of the chemical.  Hazard and precautionary statements have been introduced to cover prevention, response, storage and disposal of chemicals. 

Safe Work Australia has announced that Australia will be adopting Revision 7 of GHS. As of 1 January 2021, suppliers, manufacturers, importers and businesses dealing with chemicals have two years to transition from GHS 3 to GHS 7.  

If you need assistance with SDS authoring, label creation/updates or regulatory advice during this transition or at any other time, contact us on (03) 9573 3100 or at sa***@ch******.net.

PPE: Personal Protective Equipment 

PPE refers to items that are used or worn to minimise or mitigate a worker’s health and safety risks. PPE includes:

  • Hard hats or helmets
  • Goggles
  • Face masks
  • Respirators
  • Sunscreen
  • Ear plugs
  • High visibility clothing
  • Gowns or aprons
  • Gloves
  • Hand sanitiser
  • Shoe booties 
  • Steel-toed boots

PPE is a level 3 control measure, which means it does not control the hazard at the source; instead, it relies on human compliance. Used without any other form of hazard control, PPE is the least effective means of minimising risks. Hence, it should always be supplemented with other forms of hazard and chemical control. For more information about specific types of PPE, read our post on How to select suitable Personal Protective Equipment (PPE) for working with chemicals”. 

Person wearing personal protective equipment.
Person wearing personal protective equipment.

SDS: Safety Data Sheets

As a chemical supplier, manufacturer, end user or business owner, you are legally required to hold SDS for any chemicals you handle.

As mentioned earlier, SDS follow a 16-item format that includes information on the entire lifecycle of the chemical from safe use to compatible storage and responsible disposal. This easy-to-read format assists chemical users in reducing the risks involved in handling, storing and working with chemicals. 

The 16 sections are: 

  1. Product identification
  2. Hazard identification
  3. Composition/ingredients
  4. First aid measures
  5. Fire-fighting measures
  6. Accidental release measures
  7. Handling and storage
  8. Exposure controls/personal protection
  9. Physical and chemical properties
  10. Stability and reactivity
  11. Toxicological information
  12. Ecological information
  13. Disposal considerations
  14. Transport information
  15. Regulatory information
  16. Other information

To find out more about SDS, please read our post on What are Safety Data Sheets (SDS) and why are they important?”.

If you need to author SDS, our easy-to-use SDS authoring system allows you the chance to author two SDS for free. Get yours FREE SDS today click here

If you have 50 chemicals or less, you can organise your SDS for free here

If you need to author and/or manage with larger numbers of SDS, we’re here to help. Simply contact us on (03) 9573 3100 or at sa***@ch******.net to discuss your needs.

SVHC: Substances of Very High Concern

SVHC are chemicals with extremely serious negative health consequences. Compiled by the EU, under the REACH regulation, SVHC remain in the environment for extended periods of time. SVHC include substances that gradually build up in the systems of organisms that come into contact with them. 

More specifically, to be classed as SVHC, substances must be: 

  1. Classified as category 1 or 2 carcinogens, mutagens or toxic for reproduction (CMR)
  2. Persistent, bio-accumulative and toxic (PBT)
  3. Very persistent and very bio-accumulative (vPvB)
  4. Responsible for very serious health effects that are equivalent to the criteria listed above. These substances are classified on a case-by-case basis. For example, although not CMR, PBT or vPvB, an endocrine disrupting chemical would fit into this category. 

If a chemical meets one of the four criteria, a dossier is written detailing the substance’s properties and the associated criteria. This information is posted on the European Chemicals Agency (ECHA) website, and all stakeholders are invited to post comments within a specific timeframe. If no comments are received, the substance is included on the SVHC Candidate List. However, if comments are received, the dossier is referred to the Member State Committee for review with the aim of reaching a unanimous decision. If a decision cannot be not reached, the European Commission prepares a draft proposal and comes to a final decision on the categorisation of the substance. 

Have questions?

If you have any questions about initialisms and acronyms or would like advice on safely handling hazardous substances, please contact the Chemwatch team today. Our friendly and experienced staff draws on years of experience to offer the latest industry advice on how to stay safe and comply with Health and Safety regulations.


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