David Mack joins Ambipar board; independent special committee formed

Rhea-AI Filing Summary

Ambipar Emergency Response announced governance changes. The board appointed David Mack as an independent director, effective October 29, 2025. The board also formed an Independent Special Committee with Mr. Mack as the sole member.

The committee is tasked with identifying and evaluating matters where a conflict of interest exists or may reasonably arise between the Company and its related parties, and with investigating and evaluating potential claims and causes of action the Company may hold against related parties. These steps add an additional layer of independent oversight to address related-party matters.

Insights

Corporate governance analyst

Independent director added; special committee to review related-party matters.

Ambipar Emergency Response named David Mack an independent director and created an Independent Special Committee with him as sole member. The mandate covers conflicts that exist or could arise with related parties and an assessment of potential Company claims.

Such committees centralize decision-making outside management, which can improve process integrity when related parties are involved. Actual outcomes depend on the committee’s findings and board follow-through, which are not detailed here.

There is no financial impact disclosed in this excerpt; the move is procedural and governance-focused.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of November 2025

Commission File Number: 001-41638

AMBIPAR EMERGENCY RESPONSE

(Exact name of registrant as specified in its charter)

Avenida Angélica, nº 2346, 5th Floor

São Paulo, São Paulo, Brazil, 01228-200

Tel: +55 (11) 3526-3526

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F  ☒             Form 40-F  ☐

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Appointment of Independent Director and formation of Independent Special Committee

São Paulo, Brazil – November 4, 2025 – The board of directors of Ambipar Emergency Response (the “Company”) appointed, effective October 29, 2025, David Mack to serve as an independent director of the Company.

The board of directors further established an independent special committee (the “Independent Special Committee”) with Mr. Mack acting as the sole member. The Independent Special Committee was tasked with (i) identifying and evaluating all matters in which a conflict of interest exists or is reasonably likely to exist between the Company and its related parties and (ii) investigating and evaluating potential claims and causes of action that the Company may hold against any of its related parties.

About Ambipar Emergency Response

Ambipar Response specializes in environmental services and operates in six main business units: emergency response, fire response, marine response, medical response, industrial response and environmental response. The Company is present in 41 countries across all six continents, providing standardized services across all regions.

The Company was founded in 1995 by Tércio Borlenghi Jr.

For more information, visit ambipar.com and http://ir-response.ambipar.com/

Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are made only as of the date they first issued and are based on current expectations, estimates, forecasts and projections as well as the beliefs and assumptions of management. These statements identify prospective information and may include words such as “believe,” “may,” “will,” “aim,” “estimate,” “continue,” “anticipate,” “intend,” “expect,” “forecast,” “plan,” “predict,” “project,” “potential,” “aspiration,” “objectives,” “should,” “purpose,” “belief,” and similar, or variations of, or the negative of such words and expressions, although not all forward-looking statements contain these identifying words.

Forward-looking statements are subject to a number of risks and uncertainties, many of which involve factors or circumstances that are beyond Ambipar Response’s control.

Ambipar Response’s actual results could differ materially from those stated or implied in forward-looking statements due to a number of factors, including but not limited to: more intense competition than expected, lower addition of new clients, regulatory measures, more investments in our business than expected, and our inability to execute successfully upon our strategic initiatives, among other factors described in “Item 3.D—Key Information--Risk Factors” of Ambipar Response’s annual report on Form 20-F for the year ended December 31, 2024 and other public filings it makes with the Securities and Exchange Commission. Ambipar Response does not undertake any obligation to update or revise any forward-looking statements to reflect any change in its expectations with respect to such statements or any changes in events, conditions or circumstances after the date they were made, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws.

Investor Relations Contact:

Email: ir.response@ambipar.com

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: November 4, 2025

	AMBIPAR EMERGENCY RESPONSE
	By:	/s/Thiago da Costa Silva
	Name:	Thiago da Costa Silva
	Title:	Director

FAQ

What did AMBI announce in this 6-K?

The board appointed David Mack as an independent director, effective October 29, 2025, and formed an Independent Special Committee with him as the sole member.

What is the Independent Special Committee’s mandate at AMBI?

To identify and evaluate conflicts between the Company and related parties and to investigate and evaluate potential claims and causes of action the Company may hold against related parties.

Who serves on AMBI’s Independent Special Committee?

David Mack serves as the sole member.

Does the filing disclose financial results or transactions for AMBI?

No financial results or major transactions are disclosed; the update concerns board composition and governance processes.

When did David Mack’s appointment to AMBI’s board take effect?

His appointment was effective on October 29, 2025.

What does AMBI do?

Ambipar Response provides environmental services across six units, including emergency, fire, marine, medical, industrial, and environmental response in 41 countries.