The SEC made the Form S-4 registration statement effective on July 13, 2026. Olin and Huntsman announced the development on July 14 and scheduled special meetings for Aug. 25, when Olin shareholders and Huntsman stockholders are expected to vote on the proposed combination.

The transaction is intended to create a combined company called OlinHuntsman. It would use Olin common stock as merger consideration, rather than a cash payment to shareholders. The deal has not closed and is not guaranteed to do so: shareholder approval and other conditions, including applicable regulatory requirements, remain outstanding.

What the SEC filing changes

A Form S-4 is the registration statement used for securities issued in certain business combinations. The SEC’s effectiveness declaration clears the companies to proceed with the shareholder-meeting process described in the filing. It does not itself approve the merger or replace the shareholder vote.

The planned transaction is based on an agreement between the two chemical companies. Olin entered into the Agreement and Plan of Merger with Huntsman on June 15, 2026. The boards of directors of both companies unanimously approved the merger agreement and the related transactions.

The Aug. 25 meetings are therefore the next major scheduled decision point. Shareholders will have the opportunity to consider the proposed all-stock structure and decide whether to approve the transaction under the terms presented by the companies.

Why the vote matters

Olin and Huntsman are established chemical businesses headquartered in Clayton, Missouri, and The Woodlands, Texas, respectively. Combining them would create a new corporate structure spanning the operations of both companies, subject to the deal’s conditions and any required clearances.

That makes the vote relevant beyond the two boardrooms. Investors are being asked to decide whether to exchange their interests under an all-stock merger structure. Employees, customers and suppliers would also be watching the outcome because a completed combination would bring the two companies under the OlinHuntsman name.

The transaction could also matter to the broader chemical industry and to businesses that rely on chemical products and supply chains. The available filings establish the proposed combination and its approval requirements, but they do not establish the final size, revenue, workforce or geographic footprint of a company that might result.

What happens next

The companies’ immediate public milestone is the Aug. 25 schedule for the Olin and Huntsman special meetings. The merger must receive the required shareholder approvals before it can move toward closing.

Regulatory requirements and the other conditions in the merger agreement also remain part of the process. The SEC’s effectiveness declaration allows the companies to seek the votes; it does not establish that all remaining regulatory clearances have been obtained.

Until the shareholder meetings are held and the required conditions are satisfied, OlinHuntsman remains a proposed combination rather than a completed company. The next material development will be the shareholder vote and any subsequent announcement about whether the transaction can proceed.

What the July 13 proclamation does

The proclamation says annex-listed stationary sources are exempt from “those aspects” of the 2024 HON Rule that were promulgated under Clean Air Act section 112, for a period of 2 years beyond the HON Rule’s relevant compliance dates.

It further states that each compliance deadline established under the HON Rule applicable to Annex I facilities is extended by 2 years—and that, during each two-year exemption period, the facilities will be subject to the emissions and compliance obligations they had under the applicable pre-HON standard.

In the proclamation’s rationale, the president also finds that the technology needed to implement the HON Rule is not available in a commercially viable form that would allow full compliance by the HON Rule’s original compliance dates, and links the decision to national security and supply-chain resilience.

Who’s covered: Annex I facility list

The exemption applies only to the facilities named in Annex I. Annex I lists the following companies and affected facilities/sources:

• INEOS US Chemicals Company — Cooper River Facility (South Carolina)
• INEOS Nitriles USA LLC — Green Lake Facility (Texas); Lima Facility (Ohio)
• Occidental Chemical Corporation — Geismar Plant (Louisiana); Wichita Plant (Kansas)
• Zeon Chemicals LP — Louisville Facility (Kentucky); Zeon Chemicals LP Mississippi Plant (Mississippi)
• Westlake Vinyls Inc. — Calvert City Facility (Kentucky)
• Westlake Epoxy Inc. — Deer Park Facility (Texas)
• Westlake Chemicals and Vinyls LLC — Plaquemine Facility (Louisiana)
• Westlake Vinyls Company, LP — Geismar Facility (Louisiana)
• Eastman Chemical Company — Kingsport Facility (Tennessee)
• Hexion Inc. — Hexion Fayetteville Facility (North Carolina)
• Indorama Ventures Oxides, LLC — LAB Chocolate Bayou Facility (Texas)
• Methanex USA LLC — Geismar Facility (Louisiana)
• Methanex Beaumont, LLC — Beaumont Facility (Texas)
• Alpek Polyester USA, LLC — Columbia Site (South Carolina)
• Shintech Louisiana LLC — Plaquemine Complex (Louisiana)
• Nouryon Functional Chemicals LLC — Axis Facility (Alabama)
• AdvanSix Resins & Chemicals LLC — Frankford Plant (Pennsylvania)

If a facility is not named in Annex I, this proclamation does not automatically change that site’s HON compliance timeline.

How this fits the 2024 HON Rule (and SOCMI)

The proclamation points to EPA’s May 16, 2024 HON Rule for facilities in the synthetic organic chemical manufacturing industry (often described through the SOCMI category). EPA describes SOCMI as a large source category that includes hundreds of plants producing bulk commodity chemicals, with EPA promulgating NSPS for VOC emissions from process vents and requiring control via leak detection and repair for equipment leaks.

The president’s stated case for relief is essentially a timing/technology gap: testing, monitoring, or compliance pathways referenced in the HON Rule depend on technology the proclamation says is not practically available for some sites by the original deadlines.

What to watch next

For communities near the Annex I facilities, the immediate practical change is the shift in compliance deadlines by two years for the covered, annex-listed sources. Watch for follow-on steps from EPA and regulators—such as updated implementation expectations, permitting/compliance documentation updates, and the next milestones that could drive inspections or monitoring work for the annexed sites.

Sources

• The White House — Proclamation text (Regulatory Relief for Certain Stationary Sources to Promote American Chemical Manufacturing Security)
• U.S. EPA — Synthetic Organic Chemical Manufacturing Industry (SOCMI) NSPS page (context/rule history)
• Federal Register (May 16, 2024) — HON Rule PDF (FR Doc. 2024–07002)