Controlled use exposure scenarios

We have developed 2 controlled use exposure scenarios in consultation with industry. The control measures specified in the 2 exposure scenarios generally apply to industrial use.

Typically a chemical being used as described in these scenarios meets the exposure criteria.

Exceptions may occur where a chemical has particular physico-chemical characteristics (for example, highly volatile or persistent). Specific criteria (for example, calculation of releases to surface water) must comply with CUP requirements.

These exposure scenarios are set out as performance criteria:

  • specific controls are discussed against each criteria where information is available to us
  • listed control measures are in bullet lists
  • listed control measures are considered to meet the performance criteria as suitable controls under the CUP category
  • control measures other than those listed may also meet the performance criteria, and the permit application must describe how each unlisted control does so.

Personal protective equipment is generally not specified as part of controls—granting a CUP normally depends on suitable engineering controls. However personal protective equipment must always be used as an additional protection measure, according to the Safe Work Australia Code of Practice, and you must specify use in your application. You must also describe the use of personal protective equipment for cleaning and maintenance tasks, including likely operational risks.

Exposure scenario 1 - Containment and controlled reformulation (reformulation of a plastic additive)

This scenario is for chemicals not manufactured in Australia. The only handling of the chemicals is to reformulate them into plastic articles, whether in a master batch or directly.

Chemicals added to the plastics normally have these functions: fillers, plasticisers, antioxidants, coupling agents, colourants, ultraviolet and other weathering stabilisers, polymeric impact modifiers, anti-static agents, flame retardants and preservatives. Processing additives, such as curing agents, blowing agents, heat stabilizers, slip promoters, lubricants, and viscosity aids, may also meet this scenario.

Occupational exposure

Occupational exposure can occur at several stages: transporting and storing; weighing and transferring to a mixing vessel; mixing and extrusion; handling the finished polymer or master batch; and disposing and cleaning. Exposure scenarios are mostly for dermal exposure or exposure to vapours or dusts.

The performance (handling) criteria for packaging, transporting and storing the chemical are the same as outlined under Public exposure below.

Handling criteria for the chemical must include:

  • opening packaging to access the new chemical in designated areas by operators specifically trained in operational procedures, using precautions relating to the new chemical or to products containing it
  • not liberating contents until the bag or container is opened to add the contents to a pre-mix container, hopper or low or high-speed mixer (automated unloading is expected for large containers)
  • enclosing all dust or vapour generating processes, such as mixing, grinding and heating
  • generally performing transfer processes under local exhaust ventilation
  • enclosing mixing, grinding, extrusion and/or moulding operation; the possible volatilisation of the additive during extrusion must be addressed by keeping the vapour pressure low at the relevant temperature, or by detailing vapour control measures
  • enclosing melting and extrusion or moulding  operations
  • controlling fumes and/or vapours with exhaust ventilation
  • addressing dust exposure generated during transferring and weighing the chemical and disposing of packaging through an enclosed process with sufficient local exhaust ventilation, or using a non-dusting form such as master batch pellets or waxy solids
  • using the chemical in non-dusting form or in a master batch
  • using,for bulk quantities, mechanical systems for unloading and weighing (for example, in a weight feeder) and automating distribution through enclosed transfer systems
  • weighing and adding to mixers under a suitably designed local exhaust ventilation system that has been properly installed, tested and is properly maintained
  • using pre-cleaning (where the situation permits) and personal protective equipment for cleaning and maintenance
  • handling finished articles or master batches is considered to be qualitatively the same process as use of the finished article by the public, and therefore does not require specific controls.

Public exposure

The only products available to the public are finished moulded plastic articles. The chemical is sufficiently immobilised by its incorporation into the plastic article and the criteria for public exposure met. The exception is if the chemical or breakdown product from the plastic article is released at a sufficient rate that leads to accumulation in the environment (considering the environmental fate properties of the chemical or breakdown product) and results in potential exposure of humans to elevated levels. The potential for public exposure is only possible if the chemical is released after a transport incident or inappropriate handling.

Packaging, transporting and storing criteria for the chemical must include:

  • packaging in dangerous goods-approved packaging or in robust packaging suitable for protecting and retaining the contents
  • transporting and storing additives in robust polyethylene-lined, heavy-duty woven polypropylene bags or flexible intermediate bulk containers
  • transporting by road or rail as dangerous goods according to the Australian Code for Transport of Dangerous Goods by Road and Rail (if appropriate), or transporting by recognised industrial chemical transport operators.
  • storing the chemical in dangerous goods stores approved under state and territory government legislation, or storing in general industrial chemicals stores controlled by experienced stores operators and in a location preventing damage to packaging and release into drains, sewers or soil.

Environmental exposure

Overall, the new chemical cannot be intentionally released to the aquatic, air or terrestrial environmental compartments.

Environmental exposure may be possible in the event of release of the chemical after a transport incident. The performance criteria for packaging, transporting and storing the chemical are the same as outlined under Public exposure above

Handling criteria for the chemical must include:

  • disposing residual chemical retained in packaging with the empty packaging to regulated landfill, while ensuring the chemical must have negligible potential for migrating to groundwater from releases to land or landfill
  • ensuring waste chemical generated during setting of initial extrusion specifications, or from off-specification material and from cleaning and/or purging at the end of production runs extrusion processes, is a minor proportion of the introduced substance
  • ensuring quantities of waste chemical arising from spillage before blending or when captured in a dust or vapour extraction filter or from waste extruded preparations, is not recycled
  • recycling all production and cleaning waste, where possible, or collecting and consigning it to regulated landfill while ensuring the chemical has negligible potential for migrating to groundwater from releases to land or landfill
  • recycling or releasing to regulated landfill sites moulded articles at the end of their life, while ensuring the chemical has negligible potential for migrating to groundwater from releases to land or landfill

Exposure scenario 2 - Site-limited and closed system (enclosed use and complete consumption)

This scenario is for the use of a chemical as a chemical industry feedstock resulting in conversion to a different chemical or polymer before being released from the industrial environment. It is specific for importation, but also relevant for onsite production of an intermediate.

This scenario does not address the chemical or polymer produced from the feedstock or intermediate. This is subject to other NICNAS requirements.

Occupational exposure

Occupational exposure is limited by the use of an enclosed process, which accounts for weighing and transferring to a reaction vessel, at which point the chemical ceases to exist.

Exposure scenarios are mostly for dermal exposure or exposure to vapours or dusts during transfer from imported containers to the enclosed pipe work system attached to the reactor, and also maintenance and cleaning.

Overall handling criteria for the chemical must include:

  • opening packaging to access the new chemical in designated areas by operators specifically trained in operational procedures, using precautions relating to the new chemical or to products containing it
  • ensuring the chemical remain in an enclosed pipe work system for its entire lifecycle within a factory, with weighing by load cell or volumetric metering
  • limiting potential exposure, apart from maintenance and cleaning, to transfer operations, conducting these operations using protective transfer mechanisms, particularly low dead volume couplings
  • demonstrating,if drum spears are used, suitable control of exposure during drum changing.

Liquids

Criteria for transferring liquids include:

  • emptying into a calibrated vessel
  • emptying through volumetric meters
  • running drain lines to installed scales.

In addition, when transferring liquids, handling criteria to prevent hazardous substances in the gas phase includes:

  • transferring in enclosed systems or in systems that can be equalised
  • using gas displacement devices for pumping
  • extracting vapours at the point of escape
  • providing good general ventilation

To avoid liquid escaping during transfer, chemical pumps must conform to appropriate international standards and piping connections must employ dry break couplings. Design considerations must take account of shortening the distance of transfer to and from storage containers.

Solids

When transferring solids, ensure enclosure of process through engineering controls. Manual unloading under Local Exhaust Ventilation does not meet NICNAS's requirements.

Criteria for transferring solids to the reactor include:

  • ensuring manual unloading is not used
  • ensuring a low dust or no dust form of the solid is used
  • enclosing reactors
  • ensuring the action of pressure relief devices does not threaten personnel
  • ensuring splash deflectors are used
  • conducting,because of the quantity and nature of the substances present,  releases to the atmosphere or providing scrubbers, flare systems or blowdown tanks
  • installing seal systems on shafts of pumps, drives, mixers and stirrers to accord with the reaction mix
  • testing seal systems regularly
  • fixing leaks
  • designing sampling systems to minimise exposure.

Design systems for sampling of the reactor using these procedures:

  • withdraw the sample at a point in the plant where the pressure and temperature are as low as possible
  • ensure the cross-sectional area of the sampling device is as low as possible
  • design sampling devices so a malfunction does not result in the release of large quantities of reactor contents
  • return the inevitable pre-sample liquid to the closed system.

Transfer the sample into the sample container by:

  • preventing splashing, vapourising, dripping, overflowing and escaping of hot liquids
  • taking steps to prevent static charging
  • using a vacuum (or other means) to take samples with no pre-sample flow.

Pre-cleaning (where the situation permits) and personal protective equipment must be prescribed for cleaning and maintenance.

The criteria for transporting and storing the chemical are the same as outlined under Public exposure above.

Environmental exposure

Overall, the new chemical cannot be intentionally released to the aquatic, air or terrestrial environmental compartments.

Handling criteria for the chemical must include:

  • disposing of residual chemical retained in packaging by taking empty packaging to regulated landfill, ensuring the chemical has negligible potential for migrating to groundwater from releases to land or landfill
  • collecting quantities of the new chemical spilled or remaining from batch production and placing it into sealable containers for reusing or disposing
  • ensuring the new chemical is totally consumed during production
  • sending production and cleaning waste to a regulated landfill, ensuring the chemical has negligible potential for migrating to groundwater from releases to land or landfill.

Additional scenarios

NICNAS is interested in developing additional scenarios for use by industry.

If you would like NICNAS to consider developing a new scenario with your company, send a written request detailing:

  1. your proposed scenario
  2. how you would arrange for NICNAS to visit your site/s.

Last update 29 July 2018