Absorbent Selection Criteria

When looking to select a suitable absorbent product for cleaning up spills, we provide the following information as a guide to the major factors which assist in choosing the right product.

PLEASE ALSO SEE OUR ABSORBENT SELECTION CHART for assistance in finding the right Absorbent for your application.


In selecting an absorbent, a number of factors should be considered:

  • The absorbent should encapsulate the fluid - absorb into the particle itself and not just adhere to the outside - adsorb
  • The absorbent should absorb most fluids
  • The absorbent should be safe to use and not be a hazard or affect the handler
  • The absorbent should be low cost where possible
  • The absorbent should meet all environmental requirements
  • The absorbent should be a high capacity particle – this means less has to be placed out on a spill, less to be swept up and less to be disposed of or left in the environment. This also means labour & time savings for clean-up personnel.


A suitable absorbent should meet the criteria for the environment:

  • Non leaching - i.e. the absorbed fluid should not be released by the absorbent in natural conditions, when subjected to landfill pressure or when it becomes wet
  • Performs well in wet conditions – absorbs the spill fluid first, in preference to water
  • Tested to the relevant USEPA standards, 9095A & 1311 adopted by Aust. Authorities


Absorbent capacity varies greatly between brands and is subject often to the type of fluid and the viscosity.
There is a great deal of confusion also, regarding the interpretation of the requirements of the USEPA test standards within the absorbent industry.

To begin with, the standard requires the test is carried out using 40 weight motor oil (which is very thick and resists absorption) that the product not release liquid when allowed to stand in the general environment and the product not to release liquid when under a landfill pressure equivalent.

Some claim that absorbent products can absorb up to 8 to 13 times their own weight in oil.  Absorbents “loaded up” to these levels clearly cannot pass the USEPA standard that requires an absorbent to retain the oil under a pressure (i.e. in a landfill situation) and more than likely would exceed the test standards which limit the level of absorption capacity.

Most standard mineral based ‘kitty litter’ type products along with sand, sawdust and soil, would also fail these tests because, like polypropylene,  they will adsorb not absorb. This means that oil sticks to the outside of these types of products and so can be removed readily, especially in wet conditions.

Prenco Spill Sweep and Spill Stop have been tested for absorbent capacity by an independent laboratory and demonstrate the best levels within the standards set. Please refer to the supplied test data for the full results on request. 


The absorbent should also be safe to use on the designated fluid and not react to cause a hazard for the user and environment.

The Material Safety Data Sheets for absorbents should be examined to determine all safety use risks, reactivity information and physical properties etc

For example, some brands of “Kitty litter” and earth mineral absorbents list crystalline silica as the base for the product. This silica in the form of quartz has been listed as Carcinogenic to Humans (Group 1) according to the International Agency for Research on Cancer.
For more information on this issue please visit www.iarc.fr/ and search for Silica

Prenco Spill Sweep and Spill Stop are non-toxic, non-carcinogenic and contain no detectable crystalline silica. In particular for the Spill Stop, no quartz, cristobalite or tridymite were detectable, even after heating to 7500c, at XRD detection limits less than 0.4%. (Amdel Limited, Nata Accredited analytical laboratory, REPORT 6A05424).
They have caution only notes for hydrofluoric acid and high concentration chemicals.

MSDS and further Technical data are available on request.


The real cost of an absorbent is measured by its performance.
i.e. How much absorbent is needed to clean up a spill of fluid – what is the cost per litre of spilt fluid?

Example #1
If a spill of 10 litres of oil requires 10 kg of a low cost “kitty litter” to completely absorb the fluid @ $5 per 10 kg bag, the cost of the clean up is $5.00
Example #2
If the same 10 litres of oil only requires 5kg of a higher performance absorbent to completely absorb the fluid to the same level and which costs $10.00 per 10 kg bag, the cost of the clean up is the same at $5.00 even though a product which is twice the cost is used.

This also requires correct application techniques of the absorbent by the user to ensure minimisation of waste.

Prenco Spill Stop is a low to medium priced absorbent but its capacity makes the actual spill clean-up cost one of the best on the market. Please see the comparison lab test results between Spill Stop and Attapulgite clay  - available on request

Disposing the contaminated absorbent can also add to the cost of the absorbent/spill clean-up.
Where the absorbent meets certain criteria (see DISPOSAL heading below) there is no cost for disposal.


The methods of applying an absorbent to a spill can also vary according to the respondent and the way the absorbent is presented.

Most kitty litter absorbents are supplied in 20 kg bags. This makes pouring from the bag difficult to control with the heavy weight of the bag to control also. It is often observed that in most cases, too much absorbent is placed on the spill by this application resulting in overuse and extra time spent in sweeping up the excess unused portion.

Prenco Spill Sweep and Spill Stop are presented in 10kg bags (which also meet the OH&S lifting standards for one person) This makes control at the application stage much more manageable and often with the increased absorbency rate offers the same clean-up result.
Also presenting the absorbent loose in a 120 litre wheelie bin means the right measured and controlled amount can be applied to the spill in stages as the absorbency is monitored.


Absorbents should be disposed of according to local government regulations and guidelines. Indiscriminate disposal of contaminated absorbents, oily rags, sand, sawdust etc, compromises the licence requirements of the landfill/waste depot operator, who has limitations on the levels of hydrocarbons in particular, able to be disposed.

It is important also to ensure absorbents used to clean up chemical spills in particular should not be allowed to mix with other waste that may cause a hazard or chemical reaction.

Where possible the contaminated absorbent should be picked up and taken to a licensed waste depot or treatment facility for processing depending on the fluid absorbed.
If it is not possible to collect the contaminated absorbent and the absorbent is left in the environment, no further pollution should occur. The fluid should be immobilised in the absorbent and is in the best possible state for eventual degradation.

Where the fluid is light to medium hydrocarbons, the  EPA have issued  guideline bulletins –

NSW - Used Absorbents, containing no free liquid, that has absorbed Total Petroleum Hydrocarbons C10 – C36  (kerosene, diesel, lubricating oils) has been classified by the N.S.W. EPA as immobilised solid waste suitable for Solid Waste Landfills Class 2.  These landfills are essentially the Local Tip.  They differ from Class 1 Landfills through the exclusion of putrescible (organic) waste (generates a more aggressive leachate).

SA “Disposal of used hydrocarbon absorbent materials” which can be found at: http://www.epa.sa.gov.au/xstd_files/Waste/Guideline/guide_hydrocarbon.pdf

 This guideline refers to the disposal requirements for these fluids and the USEPA test standards. Where absorbents meet the standards and when used according to manufacturer’s instructions, they can be disposed of in 100 kg amounts at no cost, at a licensed waste facility.

Prenco Spill Sweep and Spill Stop meets the  EPA requirements for disposal when absorbing light to medium grade hydrocarbons. 


Due to the benefits of the new generation of absorbents, a certain amount of “re-training” is recommended on the application and use.

A training video and/or direct training session, should be made available to the client to assist with any upgrade to the use of quality absorbents.

The training will cover:

  • Product benefits and technical information
  • Safety requirements and risk information
  • Application and use techniques
  • Disposal requirements 


Many organisations have examined their absorbent use in recent times. With the onset of high performance products, they have been prepared to pay twice as much but receive more than twice the benefits in cost recovery, safety and environment – hard to measure sometimes, but easy to determine.

Please enquire if you would like contact details of a number of Councils and Industrial clients who would independently testify to the benefits of the new absorbents as a reference of support.


Some of the information provided above, is of a general advice nature only. No warrantee is either expressed or implied and no liability is accepted for any damage or injury arising from use or misuse of the information. In addition, as local regulations vary greatly, clients are requested to seek independent and legal advice direct with the appropriate sources.

Please do not hesitate to contact if you require further assistance or require any further information.


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