16 December 2025
Sovereign Sharna
Email Address:
[FYI request #32674 email]
Tēnā koe,
OFFICIAL INFORMATION REQUEST
Thank you for your request for official information regarding fluoride used in public water
supplies. The Ministry of Health transferred al parts of your request to Gisborne District Council
(GDC) under section 12 of the Local Government Official Information and Meetings Act 1987
(LGOIMA), for any information we may hold relating specifically to the fluoridation of the
Gisborne water supply.
Council has considered your request under LGOIMA and has decided to grant the request in
part. Where information is not held by Council, the request is refused under section 17(e) of
the Act.
Responses to each question transferred to Council
Questions 1, 2, 4, 6–14, 19, and 21
Answer: Council does not hold the information requested in relation to these questions.
Accordingly, these parts of the request are refused under section 17(e) of the Local
Government Official Information and Meetings Act 1987, as the information is not held by
Gisborne District Council.
Question 3
Provide the full chemical composition, including chemical names, chemical formulae, and
concentrations of all fluoride compounds added to the public water supply.
Answer: Gisborne District Council doses Hydro fluorosilicic Acid (HFA) at a concentration of
approximately 22%.
Chemical Formula: H₂SiF₆
The chemical composition, as supplied in the product SDS, is shown below:
Chemical name
CAS No.
Weight-%
Fluorosilicic acid
16961-83-4
21.0–23.0%
Chemical name
CAS No.
Weight-%
Hydrofluoric acid
7664-39-3
0.1–<1.0%
Water
7732-18-5
balance to 100%
(This corresponds to the attached SDS excerpt you provided.)
Question 5
Provide details of any chemical by-products, waste, or residues generated during production,
storage, transport, or dosing, including their environmental and human health impacts.
Answer: Council only holds information relating to the dosing of HFA.
During dosing, no by-products, waste, or residues are generated.
Council holds no information about production, storage, or transport impacts.
Parts not held are refused under section 17(e) of the LGOIMA.
Question 15
Include all corporate affiliations, financial interests, and advisory bodies that influence
decisions regarding fluoride.
Answer: Council is mandated to fluoridate its water supply under a direction issued by the
Director-General of Health, pursuant to Part 2A of the Health Act 1956.
No other affiliations or financial interests influence Council’s decision, as the decision does not
sit with Council.
Question 16
Provide copies of al risk assessments, environmental impact statements, monitoring reports,
and internal or external evaluations regarding fluoride safety, dosing, and public health.
Answer: Council holds none of the information requested.
This part of the request is refused under section 17(e) of the LGOIMA.
Question 17
Provide documentation of regulatory compliance, inspections, or audits by government or
third-party authorities.
Answer: Council holds no records of compliance audits or inspections specific to fluoride.
This part of the request is refused under section 17(e) of the LGOIMA.
Question 18
Disclose any incidents, complaints, or breaches relating to fluoride chemical safety, handling,
or dosing.
Answer: Council has no recorded incidents, complaints, or breaches relating to fluoride
chemical safety, handling, or dosing.
Question 20
Include international case law, peer-reviewed studies, legal decisions, or environmental
assessments showing health or environmental risks, chemical by-products, or public health
outcomes linked to fluoride.
Answer: Council does not hold this information.
This part of the request is refused under section 17(e) of the LGOIMA.
Right to seek review
You have the right to request a review of our decision by the Ombudsman. Information about
how to do this is available at
www.ombudsman.parliament.nz.
Ngā mihi
Judith Robertson
Drinking Water Manager
Document Outline
