California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 7 - General Industry Safety Orders
Group 16 - Control of Hazardous Substances
Article 111 - Fumigation
Section 5222 - Fumigation in Vaults and Chambers

(a) Vaults and chambers used for fumigation of food products, textiles or other objects shall be so constructed that employees will not be exposed to hazardous concentrations of fumigants during fumigation.

(b) A suitable warning notice with the words, "Danger," "Do Not Open," "Poison Gas," or equivalent shall be attached to the door of such rooms or vaults.

(c) After the exposure is completed, vaults or chambers shall be purged of fumigant and the air therein shall be tested. Employees shall not be allowed to enter a vault or chamber, except to make tests, until the concentration of fumigant in the air is known to be safe. Employees making tests shall wear respiratory protection approved for use in the fumigant used.

(d) Purging shall be carried out in such a way as not to endanger employees.

(e) If a flammable gas, or substance giving rise to a flammable gas is used for fumigation, all sources of ignition shall be removed or extinguished before fumigation is begun, and no source of ignition shall be allowed in a vault or chamber which has been fumigated while the concentration of flammable gas is over 20 percent of the lower explosive limit.