KOSHA-Braille: infrastructure-grade accessibility for Korean chemical safety information brief report

Korean chemical safety information is produced almost entirely as visual regulatory text. This brief report describes KOSHA-Braille, a public Korean Material Safety Data Sheet (MSDS) braille corpus and encoder release intended to provide a baseline accessibility resource for that domain. We implement a deterministic Korean braille encoder for the 2017 Korean Braille Standards, apply it to the full KOSHA MSDS database accessed through the Korea Public Data Portal, and cross-validate the output against an independently developed open-source Korean braille converter. The corpus, encoder, decoder, evaluation harness, and reference web deployment are released openly. The released artifact covers 48,966 chemicals over a 769,897-row source-section database (401,272 sections with substantive Korean text), totaling approximately 119.3 million Korean characters and 232.3 million braille cells. The encoder agrees with the independent reference at 100% over 442 cross-reference test cases, and the published Korean round-trip golden set is recovered at 45/45. The contribution is the construction, validation, and public release of a standards-compliant accessibility resource, not an end-user reading-performance claim. Reading-comprehension and field-usability studies with visually impaired readers remain necessary follow-up work.