Editing Precautionary principle (section)

====Australia====
The most important Australian court case so far, due to its exceptionally detailed consideration of the precautionary principle, is Telstra Corporation Limited v Hornsby Shire Council.<ref>[2006] NSWLEC 133 (24 March 2006) [http://www.austlii.edu.au/au/cases/nsw/NSWLEC/2006/133.html].</ref>

The principle was summarised by reference to the [[New South Wales|NSW]] ''Protection of the Environment Administration Act 1991'', which itself provides a good definition of the principle:<ref>{{Cite web|url=http://www.austlii.edu.au/au/legis/nsw/consol_act/poteaa1991485/s6.html|title=PROTECTION OF THE ENVIRONMENT ADMINISTRATION ACT 1991 - SECT 6 Objectives of the Authority|website=austlii.edu.au|access-date=2017-04-03}}</ref>

"If there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reasoning for postponing measures to prevent environmental degradation. In the application of the principle... decisions should be guided by:
(i) careful evaluation to avoid, wherever practicable, serious or irreversible damage to the environment; and
(ii) an assessment of risk-weighted consequence of various options".

The most significant points of Justice Preston's decision are the following findings:<ref>Hon. Justice Brian J Preston, (2006), 'Telstra Corporation Limited v Hornsby Shire Council [2006] NSWLEC 133', ''Land and Environment Court of New South Wales''. Paragraphs 125-183. https://www.caselaw.nsw.gov.au/decision/549f8a6b3004262463ad5606</ref>
* The principle and accompanying need to take precautionary measures is "triggered" when two prior conditions exist: a threat of serious or irreversible damage, and scientific uncertainty as to the extent of possible damage.
* Once both are satisfied, "a proportionate precautionary measure may be taken to avert the anticipated threat of environmental damage, but it should be proportionate."
* The threat of serious or irreversible damage should invoke consideration of five factors: the scale of threat (local, regional etc.); the perceived value of the threatened environment; whether the possible impacts are manageable; the level of public concern, and whether there is a rational or scientific basis for the concern.
* The consideration of the level of scientific uncertainty should involve factors which may include: what would constitute sufficient evidence; the level and kind of uncertainty; and the potential to reduce uncertainty.
* The principle shifts the burden of proof. If the principle applies, the burden shifts: "a decision maker must assume the threat of serious or irreversible environmental damage is... a reality [and] the burden of showing this threat... is negligible reverts to the proponent..."
* The precautionary principle invokes preventative action: "the principle permits the taking of preventative measures without having to wait until the reality and seriousness of the threat become fully known".
* "The precautionary principle should not be used to try to avoid all risks."
* The precautionary measures appropriate will depend on the combined effect of "the degree of seriousness and irreversibility of the threat and the degree of uncertainty... the more significant and uncertain the threat, the greater...the precaution required". "...measures should be adopted... proportionate to the potential threats".