Getting connected with the precautionary principle

by Brendan Bateman, Trisha Cashmere

28 Jul 2006

The precautionary principle requires precautionary measures to be taken only where there is a threat of serious or irreversible environmental damage based on objective scientific evidence.

While terms such as "ecologically sustainable development" and "the precautionary principle" are frequently used in planning law, what do they actually mean? In a recent case, Telstra Corporation Limited v Hornsby Shire Council [2006] NSWLEC 133, the Chief Judge of the NSW Land and Environment Court, Justice Preston, has given a detailed consideration of the principles of ecologically sustainable development ("ESD") and, in particular, the precautionary principle.


Cheltenham, is a suburb in northwest Sydney, "...a suburb with heritage charm...", with the Cheltenham Recreation Club at its heart. However, as Justice Preston said, "...Cheltenham is not isolated from the modern world. Residents of, visitors to and travellers through the suburb wish to engage with each other and others outside the suburb through the marvel of modern telecommunications. Here the problem arises. Cheltenham suffers from inadequate mobile telephone coverage."

Telstra sought to redress this inadequacy of service through the installation of two panel antennas on the roof of the Club. Telstra sought and received the agreement the Club to its proposal. Telstra lodged a development application with Hornsby Council in relation to the proposed facility in accordance with the Environmental Planning and Assessment Act 1979 ("Planning Act").

Unfortunately for Telstra and the Club, the proposal met significant resistance in the local community on the basis of a concern that the proposed facility would emit levels of electromagnetic energy ("EME") that would harm the health and safety of the residents of Cheltenham. Although the development application was recommended for approval by council officers, the Council refused the application. Telstra appealed against the determination to the Land and Environment Court. Such an appeal is a merits review where the Court effectively stands in the position of the Council and can exercise all the powers and discretions of the Council under the Planning Act.

The appeal

The Court heard and accepted expert evidence adduced on behalf of Telstra and the Court-appointed expert that the radiofrequency EME from the proposed base station "would not conceivably cause any adverse biological health effect."

The Council primarily relied on non-expert evidence from people objecting to the proposal. In addition to objections such as impacts on visual amenity, the objectors asserted that radiofrequency EME presented a threat of harm to residents and irrespective of proposed facility's compliance with any applicable industry or Australian standards regarding EME emissions, the Court should apply the precautionary principle to abate that threat.

Ecologically sustainable development

Justice Preston succinctly summarised ESD as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs". Justice Preston noted that there are a number of elements or principles of ESD, including:

  • the principle of sustainable use, which is the idea of exploiting natural resources in a manner which is sustainable
  • the principle of integration, in which there is an integration of economic and environmental considerations in the decision-making process
  • the precautionary principle (discussed in detail below)
  • the principle of equity, which considers both intergenerational equity and intra-generational equity
  • the principle that conservation of biological diversity and ecological integrity should be a fundamental consideration; and
  • the principle of the internalisation of environmental costs.

The principles of ESD are to be applied when decisions are being made under any legislative enactment or decision which adopts the principles. The Planning Act states that its objects include encouraging ESD.

Section 79C(1) of the Planning Act sets out the relevant matters which a consent authority must take into consideration when assessing a development application. Though it does not expressly refer to the principles of ESD, it does require a consent authority to take into account "the public interest" in section 79C(1)(e). Justice Preston held that:

"The consideration of the public interest is ample enough, having regard to the subject matter, scope and purpose of the [Planning] Act, to embrace ecologically sustainable development.

Accordingly, by requiring a consent authority (or on a merits review appeal the Court) to have regard to the public interest, s 79C(1)(e) of the EPA Act obliges the consent authority to have regard to the principles of ecologically sustainable development in cases where issues relevant to those principles arise [emphasis added]."

The precautionary principle

Justice Preston noted that while a number of decisions of the Court had established that the precautionary principle is to be considered in determining a development application under the Planning Act, there had been no detailed explanation of the precautionary principle or its application. Justice Preston took the opportunity to rectify the situation.

Justice Preston stated that the application of the precautionary principle and the need to take precautionary measures is triggered by the satisfaction of two conditions precedent:

  • a threat of serious or irreversible environmental damage; and
  • scientific uncertainty as to the nature and scope of the threat of environmental damage.

When both of these conditions have been satisfied, a precautionary measure should be taken but it must be proportionate to the level of the threat.

Threat of serious or irreversible environmental damage

In assessing how serious and/or irreversible a threat is, Justice Preston stated that it is necessary to consider both expert input in addition to the views of stakeholders, and to ascertain whether scientifically reasonable scenarios or models of possible harm have been generated. Ultimately, however, the threat must be sustained by scientific evidence.

Factors which Justice Preston suggested could be considered to assess the seriousness or irreversibility of environmental damage might include:

  • the spatial scale of the threat (eg local, regional, statewide, national, international);
  • the magnitude of possible impacts, on both natural and human systems;
  • the perceived value of the threatened environment;
  • the temporal scale of possible impacts, in terms of both the timing and the longevity (or persistence) of the impacts;
  • the manageability of possible impacts, having regard to the availability of means and the acceptability of means;
  • the level of public concern, and the rationality of and scientific or other evidentiary basis for the public concern; and
  • the reversibility of the possible impacts and, if reversible, the time frame for reversing the impacts, and the difficulty and expense of reversing the impacts.

Scientific uncertainty

In relation to assessing the degree of scientific uncertainty for the purpose of the second pre-condition, Justice Preston stated that the following factors may be relevant considerations:

  • the sufficiency of the evidence that there might be serious or irreversible environmental harm caused by the development plan, programme or project;
  • the level of uncertainty, including the kind of uncertainty (such as technical, methodological or epistemological uncertainty); and
  • the potential to reduce uncertainty having regard to what is possible in principle, economically and within a reasonable time frame.

Shift of the burden of proof

When both conditions precedent to the precautionary principle are satisfied, there is a shift of the burden of proof. The decision-maker must assume that the threat of serious or irreversible environmental damage is no longer uncertain but is a reality, and the burden of showing that this threat does not in fact exist or is negligible effectively reverts to the proponent of the project. Justice Preston stated:

"The function of the precautionary principle is, therefore, to require the decision-maker to assume that there is, or will be, a serious or irreversible threat of environmental damage and to take this into account, notwithstanding that there is a degree of scientific uncertainty about whether the threat really exists."

However, the shift in the burden of proof is only in relation to the question of environmental damage. And the question of environmental damage is only one input into the decision making process, which is not given over-riding weight compared to other factors which must be considered.

Preventative measures

The precautionary principle permits the taking of preventative measures, without waiting to ascertain the reality and seriousness of environmental threats. However, Justice Preston expressed the view that the precautionary principle should not be used to try and avoid all risks, as "some are plainly acceptable and others are plainly unacceptable".

A preventative measure should only be taken where the risk appears to be adequately backed up by the scientific data available at the time when the preventative measure is to be taken. In respect to the degree of precaution, a risk assessment is required, in which potential errors are weighted in favour of environmental protection. Justice Preston expressed the view that the implementation of an adaptive management approach is one means of retaining a margin for error.

Finally, as the precautionary principle is only one of the set of principles of ESD, Justice Preston considered that it should not be viewed in isolation. This means that precautionary measures must not only be appropriate having regard to the precautionary principle itself, but also in the context of the other principles of ESD including for example inter-generational and intra-generational equity. In some circumstances these other principles may strengthen the case for precautionary action, while in others the precautionary principle may need to be weighed against the other principles as well as other human rights such as food, water, health and shelter.

Application of the principles in the Telstra case

Justice Preston found that the first condition precedent for the application of the precautionary principle, that there be a threat of serious or irreversible environmental damage, was not satisfied as there was no evidence of such a threat. Consequently, there was no basis for the application of the precautionary principle in respect of Telstra's development application.

Justice Preston also concluded that the objectors' claims in relation to the alleged impact of RF EME on people and the environment were without reasonable evidentiary foundation. Therefore, little weight was to be given to the residents' perceptions. As a result, there was no probative evidence upon which the Court could make findings of adverse effects on the amenity of the locality or on the health and safety of persons in the locality or on the environment.

In these circumstances, Justice Preston concluded that there is no logical basis for refusing consent to Telstra's proposed development.


The decision of Justice Preston in Telstra represents the most comprehensive analysis yet of the precautionary principle in a judicial context. It contains clear guidance to decision makers on when and how the precautionary principle is to be applied when there is a statutory obligation to have regard to the principles of ESD. In doing so, Justice Preston has taken the principles of ESD beyond mere "aspirational" objectives to be ones of substance capable of precise consideration. It is noteworthy that the decision in Telstra was quickly followed by another decision of Justice Preston in Bentley v BGP Properties Pty Limited, where he applied the principles of ESD when sentencing a defendant for environmental offences. We anticipate that the decision in Telstra will be cited with approval by courts both in NSW and in other jurisdictions where ever consideration of the principles of ESD is statutorily mandated in any decision-making process.

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