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Chemco, Inc.

Chemco develops pressure-impregnated fire-retardant wood treatments, including Thermex-FR exterior lumber listed by CAL FIRE OSFM in category 2520.

Listing health: 1 listed. Soonest expiry: 2027-06-30. Statuses derive from the live program data by a published rule.

Product record	Status	Expires
Chemco Thermex-FR exterior treated redwood and western red cedar	Listed	2027-06-30

Sources

SaferWood Thermex-FR specification guidance — Chemco, Inc. (manufacturer). Accessed 2026-08-25.
OSFM Building Materials Listing search — CAL FIRE OSFM (listing-body). Accessed 2026-08-25.