Official filing · original source linked

Arsenal Biosciences WARN notice — CA, 2025-09-16

Name: Arsenal Biosciences, Inc. WARN notice
Creator: California Employment Development Department

Arsenal Biosciences, Inc. reported 100 workers affected in San Mateo. Notice date: Sep 16, 2025; planned effective date: Nov 14, 2025.

Raw employer name: Arsenal Biosciences, Inc.
Canonical company: Arsenal Biosciences →
Workers affected: 100
Event type: layoff
Filing status: filed
Notice / received date: Sep 16, 2025
Effective date: Nov 14, 2025
City: Unavailable
County: San Mateo →
State: California →
ZIP: 94080
Reported location: San Mateo
Published address: 329 Oyster Point Blvd. South San Francisco CA 94080
Source classification: Layoff Permanent
Source agency: California Employment Development Department

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Original source & provenance

Open supplied source ↗

Agency source
California Employment Development Department

Source ID / record ID
ca-edd / arsenal-biosciences-inc|329-oyster-point-blvd-south-san-francisco-ca-94080|2025-09-16

First ingested
Oct 6, 2026 · 16:02 UTC

Last observed
Oct 7, 2026 · 21:57 UTC

Snapshot SHA-256
c4239543ffcf87e406005c99b2282f757cbd0e4f7b102f3ea4bdaa33aeabc4df

View original source row

{
  "cells": {
    "notice_date": "09/16/2025",
    "received_date": "09/17/2025",
    "effective_date": "11/14/2025",
    "company": "Arsenal Biosciences, Inc.",
    "reported_location": "San Mateo County",
    "workers": "100",
    "type": "Layoff Permanent",
    "address": "329 Oyster Point Blvd. South San Francisco CA 94080"
  },
  "noticeDateField": "Notice Date",
  "archive": "https://edd.ca.gov/siteassets/files/jobs_and_training/warn/warn-report-for-7-1-25-to-6-30-26.pdf",
  "page": 5
}

A source-linked public record. Secondary records are attributed to their provider and are not independently verified. For direct records, “Verified” means sourced from an official agency; it does not confirm the layoffs took place.

Related company filings

Company / location	Workers	Effective date	Notice date	Type / source
Arsenal BiosciencesSouth San Francisco, CA	58	Oct 29, 2026	Aug 31, 2026	layoffSource ↗

Dates and counts are the supplied source’s reported values. Secondary-provider locations are unstructured; they are not confirmed worksite addresses. Check the original document for phased dates, updates and exceptions.

Arsenal Biosciences WARN notice — CA, 2025-09-16

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