The reassessment process

We follow a process to reassess hazardous substances. Find out what happens here.

This process is outlined in the Hazardous Substances and New Organisms Act 1996 (HSNO Act) and must be followed by the EPA or any other party who applies for a reassessment.

Most reassessments will follow the process described here. Sometimes, chemicals could be reviewed by other mechanisms, such as by amendments to Group Standards.

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Call for information

We may request a call for information from industry, organisations and the public to find out how a chemical is being used, and to what extent, and the impact to Māori, people's health, the environment, and economy.

A call for information may happen before or after we or an applicant have applied for grounds for reassessment.

Grounds for reassessment

A formal application must be made to establish if there are legal grounds to reassess the chemical.

An applicant may show that there are grounds because:

  • there is significant new information about the effects of the chemical
  • there has been a significant change in the chemical's use and quantity
  • there is an alternative
  • or as a consequence of changes to the Health and Safety at Work Act.

Making a decision on an application for grounds

The information we receive, as well as our own research, is used to decide if there are grounds to reassess. The decision is made by a sub-group of our HSNO Committee. If they decide that grounds do exist, then a reassessment can be undertaken.

Information about the HSNO Decision-making Committee


Anyone can apply for a formal reassessment, but only if grounds have been established. It can be a different applicant than the one who applied for grounds to be established. Information supporting the reassessment and any changes being proposed must be provided as part of the application.

The reassessment considers issues such as:

  • manufacture and import volumes
  • use and application information
  • environmental exposure mitigation measures
  • scientific and technical information
  • cultural impacts
  • the existence of alternatives.

People generally have the opportunity to provide information by making a submission on reassessment applications, and this is encouraged to get a better picture of the chemical and its uses. Some reassessments may include a public hearing.

The reassessment decision

The decision about the reassessment is made by a sub-group of our HSNO Committee.

The Committee may decide to:

  • make no change to the existing approval
  • increase or change the controls, or rules, around the chemical's use
  • revoke the existing approval - that is, ban its use.

Process timeline

The timeline for each reassessment varies depending on its complexity. There are specific steps and timeframes that must be followed, which are outlined in the HSNO Act, but each reassessment is considered on a case by case basis.