Ex-Ethereum Foundation Lead Sues Over Firing After Cancer Disclosure

Former Ethereum Foundation Protocol Support lead Kayleen Fulton sued Ethereum co-founder Vitalik Buterin and several foundation-linked entities in Colorado federal court on Nov. 4, alleging her termination violated U.S. disability and medical-leave laws. The complaint states she was fired 13 days after disclosing in writing that she had ovarian cancer.

Fulton says she informed management of her diagnosis on March 24. According to the filing, her dismissal followed on April 6 — a window of under two weeks between disclosure and termination.

The lawsuit brings claims under the Americans with Disabilities Act and the Family and Medical Leave Act. Fulton seeks damages and a court order declaring her separation agreement invalid. Buterin and the foundation-linked entities are named among the defendants. The complaint concerns an internal policy dispute at the organization that supports development of the Ethereum network, not the protocol's code or operations.

What preceded the firing?

The complaint ties the termination to a second, separate flashpoint. On March 25 — one day after her cancer disclosure — Fulton helped organize a letter signed by 53 employees opposing a requirement that staff endorse the foundation's Mandate.

Fulton says the Mandate document contained a clause invoking ritual suicide. She and fellow organizer Trent Van Epps were fired roughly 30 minutes apart, according to the complaint. That timing is central to her argument that the dismissal was retaliatory rather than performance-based. The foundation has not, at the time of writing, publicly detailed its account of the events.

What are the legal stakes?

The ADA and FMLA claims put the case in U.S. federal employment law territory. The ADA prohibits discrimination against qualified individuals with disabilities; the FMLA entitles eligible employees to unpaid, job-protected medical leave. If the court accepts that Fulton's written diagnosis triggered protected status, the 13-day gap between disclosure and firing becomes the factual hinge of the case.

Fulton's request to invalidate her separation agreement is also material. Such agreements typically include releases and non-disparagement clauses; voiding one could expose internal communications and expand the scope of discovery. Whether the agreement contains arbitration provisions that could move the dispute out of open court is not stated in the complaint's public summary.

What is not yet on the record?

The lawsuit is a set of allegations, not findings. The defendants have not publicly responded, and no court has weighed the evidence. The complaint does not specify the damages amount Fulton seeks, nor does it detail the exact role each defendant played in the termination decision. Attribution of the firing decision — whether to Buterin personally, to foundation-linked entities, or to specific managers — remains an open question for litigation.

The 53-signature letter adds scale to the internal conflict: more than four dozen employees formally opposed the Mandate requirement, and two of its organizers lost their jobs within a day. The foundation's handling of that policy, and of the clause Fulton describes, will likely surface in defendants' responses.

The case now sits in Colorado federal court, where defendants face standard deadlines to answer or move to dismiss. Those filings, and any challenge to the separation agreement's enforceability, will define the next phase of the dispute.