Ecolab USA v. ZappBug Inc. — Four-Patent Heat Treatment Infringement Action
Ecolab USA, Inc. sued ZappBug Inc. in the Western District of Washington asserting four patents covering heat-based pest control technology against the ZappBug Room enclosure product. The case resolved via voluntary dismissal without prejudice after 269 days, with each party bearing its own costs — leaving the door open for future enforcement.
Ecolab’s four-patent heat treatment salvo ends without prejudice
On 21 February 2025, Ecolab USA, Inc. — a global hygiene and pest elimination company — filed a patent infringement action against ZappBug Inc. in the U.S. District Court for the Western District of Washington (Case No. 2:25-cv-00333), presided over by Hon. Michelle L. Peterson. Ecolab asserted four U.S. patents — US12063921B2, US9226489B2, US10070639B2, and US11737445B2 — all directed to heat treatment pest control technology, against ZappBug’s flagship consumer product, the ZappBug Room enclosure.
The action was terminated on 17 November 2025 when Ecolab filed a voluntary notice of dismissal without prejudice pursuant to Rule 41(a)(1)(A)(i) of the Federal Rules of Civil Procedure. Because ZappBug had neither served an answer nor a motion for summary judgment at the time of filing, Ecolab was entitled to dismiss as of right — no court order was required. Each party was directed to bear its own costs, expenses, and attorneys’ fees, suggesting no negotiated settlement terms were memorialized in the public record.
The 269-day duration without a responsive pleading from ZappBug is notable and may suggest the parties explored pre-litigation resolution, or that ZappBug lacked registered counsel capable of mounting a rapid defence. The dismissal without prejudice preserves Ecolab’s full right to refile — meaning the underlying IP dispute over the ZappBug Room remains commercially unresolved. What drove the decision to withdraw at this stage, and whether licensing discussions occurred off the record, is not disclosed in publicly available court filings.
Filing to Voluntary dismissal in 269 days
269 days from filing to voluntary dismissal — resolved before any answer was served
Voluntarily dismissed: what the Rule 41 exit means for both parties
Rule 41(a)(1)(A)(i): dismissal as of right, no court order needed
Under Federal Rule of Civil Procedure 41(a)(1)(A)(i), a plaintiff may voluntarily dismiss an action without a court order at any time before the defendant has served an answer or a motion for summary judgment. ZappBug had done neither, so Ecolab’s notice was self-executing. The case closed automatically upon filing of the notice — no judicial approval was required.
Pre-answer dismissalWithout prejudice confirmed — but the public record is explicit here
The dismissal notice expressly states ‘without prejudice,’ meaning Ecolab retains the right to refile the same claims against ZappBug at a future date, subject to applicable statutes of limitations. This is distinct from a dismissal with prejudice, which would bar re-litigation. Unlike some voluntary dismissals where the prejudice status is ambiguous in the public record, this filing leaves no ambiguity: the door to future enforcement is explicitly preserved.
Refiling right preservedZappBug escapes judgment — for now, but exposure persists
ZappBug faces no injunction, damages award, or formal invalidity finding as a result of this dismissal. However, the without-prejudice nature means the threat of re-litigation is real. ZappBug’s continued sale of the ZappBug Room product in a space where Ecolab holds at least four active patents creates ongoing IP exposure. The absence of a registered defence counsel on record is a commercially significant gap for a company facing a well-resourced IP plaintiff.
No judgment, ongoing riskHeat treatment IP landscape remains unsettled for the sector
Ecolab’s decision to assert four patents simultaneously against a single consumer product signals an aggressive IP posture in the heat treatment pest control space. The voluntary withdrawal without prejudice — rather than a settlement with prejudice — suggests the competitive dynamic between the parties is unresolved. Other manufacturers of heat-based pest elimination enclosures and chambers should treat Ecolab’s portfolio as an active enforcement risk, particularly given the breadth of patents spanning multiple application years.
Ongoing enforcement riskFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Ecolab USA, Inc. | Company | Global hygiene and pest elimination company — holder of US12063921B2 and three further heat treatment patentsSearch in Eureka ↗ |
| Defendant | ZappBug Inc | Company | Consumer pest control device manufacturer — maker of the ZappBug Room heat treatment enclosureSearch in Eureka ↗ |
| Plaintiff counsel | Rachel Zimmerman Scobie | Attorney | Counsel for Ecolab USA, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Vanessa Soriano Power | Attorney | Counsel for Ecolab USA, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Merchant & Gould (MN) | Law Firm | Representing Ecolab USA, Inc.Search in Eureka ↗ |
| Plaintiff law firm | STOEL RIVES LLP (WA) | Law Firm | Representing Ecolab USA, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Hon. Michelle L. Peterson | Judge | Washington Western District CourtSearch in Eureka ↗ |
Official order — verbatim text
The dismissal notice is filed pursuant to Rule 41(a)(1)(A)(i) and is self-executing — it required no judicial order and carries no merits determination. The explicit ‘without prejudice’ language preserves Ecolab’s full right to refile. Critically, the notice confirms ZappBug had served neither an answer nor a motion for summary judgment, satisfying the procedural prerequisite for unilateral withdrawal. The mutual cost-bearing provision is standard in Rule 41(a)(1) dismissals and does not imply any negotiated resolution.
US12063921B2 and three further patents — heat treatment pest control technology
The four asserted patents — US12063921B2 (App. US18/348754), US9226489B2 (App. US13/421409), US10070639B2 (App. US14/954352), and US11737445B2 (App. US17/236187) — span a broad range of application filing dates, suggesting Ecolab has built a deliberately layered portfolio covering heat treatment pest control methods and apparatus over multiple technology generations. The application numbers indicate filings across roughly a decade, with the earliest applications predating the most recent grant by several years.
For the pest control and hygiene technology sector, this portfolio represents a significant enforcement asset. Heat treatment — using elevated temperatures to eliminate bed bugs, insects, and other pests without chemical agents — is a growing commercial segment attracting both professional pest elimination companies and consumer product startups. Ecolab’s willingness to assert four patents simultaneously against a single product signals that it views this IP as commercially valuable and competitively protective. Any company developing or selling heat-based pest enclosure technology should treat this portfolio as a live enforcement risk.
Should you run an FTO analysis against Ecolab’s heat treatment patent portfolio?
If your company designs, manufactures, or sells heat treatment pest control enclosures, chambers, or related apparatus — whether for consumer or professional markets — the four patents asserted in this case represent a tangible clearance concern. Ecolab’s demonstrated willingness to file in federal court, combined with a portfolio spanning multiple application generations, means design-around analysis alone may be insufficient without a full freedom-to-operate review across all four patent families.
PatSnap Eureka’s FTO Search Agent allows IP and R&D teams to map their product features against the claims of US12063921B2, US9226489B2, US10070639B2, and US11737445B2 simultaneously, surfacing claim overlap risk and identifying prior art that may support invalidity arguments. For companies competing in the heat treatment pest control space, running this analysis before product launch or market expansion is a prudent step given the active enforcement posture Ecolab has signalled.
Run a freedom-to-operate analysis on US12063921B2 to assess your product’s exposure
Run FTO in Eureka →Similar heat treatment pest control patent cases in U.S. District Courts
Explore related patent infringement actions involving heat treatment pest control technology and voluntary dismissal outcomes in U.S. District Courts.
What this case signals for the pest control heat treatment IP landscape
Ecolab’s four-patent filing against a single product reveals a deliberate portfolio enforcement strategy in a niche but commercially active technology space.
Pre-answer dismissals without prejudice are tactically potent
Filing and then voluntarily withdrawing before any responsive pleading preserves all claims while generating commercial pressure on the defendant. For smaller companies like ZappBug, the cost and distraction of being named in a federal patent suit may itself drive licensing or product redesign conversations — regardless of whether the case proceeds to judgment.
Four-patent assertions against one product signal portfolio depth
Ecolab asserting US12063921B2, US9226489B2, US10070639B2, and US11737445B2 against a single consumer enclosure product suggests the portfolio was intentionally layered to foreclose design-around options. Competitors in heat treatment pest control should audit whether their products touch any of these four patent families before entering or expanding in this segment.
Ecolab v ZappBug — key questions answered
Ecolab USA, Inc. asserted four patents: US12063921B2, US9226489B2, US10070639B2, and US11737445B2. All relate to heat treatment pest control technology and were asserted against ZappBug’s ZappBug Room enclosure product in the Western District of Washington.
Ecolab filed a voluntary notice of dismissal without prejudice under Rule 41(a)(1)(A)(i) on 17 November 2025. Because ZappBug had not yet served an answer or motion for summary judgment, Ecolab could dismiss as of right. A dismissal without prejudice preserves Ecolab’s right to refile the same claims in the future, subject to applicable statutes of limitations.
The ZappBug Room is a consumer heat treatment enclosure designed to eliminate bed bugs and other pests through elevated temperatures without chemicals. Ecolab alleged that the product infringed four of its patents covering heat-based pest control methods and apparatus, though no merits determination was made before the case was dismissed.
ZappBug faces no court judgment, damages award, or injunction as a result of this dismissal. However, because the dismissal is without prejudice, Ecolab retains the right to refile. ZappBug’s continued sale of the ZappBug Room in a market where Ecolab holds four active patents represents ongoing IP exposure that a dismissal without prejudice does not eliminate.
Ecolab was represented by Merchant & Gould (MN) and Stoel Rives LLP (WA), with named attorneys Rachel Zimmerman Scobie and Vanessa Soriano Power. No defence counsel was listed on the public docket for ZappBug Inc. at the time of the dismissal filing.
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