August 1993 CRITICAL INJURY - CONTROLLED ATMOSPHERE WAREHOUSES Produced by the Industrial Health and Safety Program, Occupational Health and Safety Branch, Ontario Ministry of Labour HAZARD SUMMARY: Three workers lost consciousness when asphyxiated by lack of oxygen in an apple storage warehouse where the atmosphere was maintained at 3% oxygen and 97% carbon dioxide. One worker re-entered the warehouse to retrieve a tool kit without his air-supply breathing apparatus. When he collapsed and lost consciousness, the two other workers entered the warehouse without air-supply respirators to rescue him and also lost consciousness. All three were promptly rescued and have since recovered. LOCATION(S) AND SECTOR(S): All sectors where CA (controlled atmosphere) entries are required. SUGGESTED PRECAUTIONS: When a worker is required to enter a controlled atmosphere warehouse that cannot be purged: 1. The worker shall be trained to understand the risk of entry into such facilities without respiratory protection. It should be stressed that even a few seconds of oxygen depletion can impair brain cell function, and that this may result in confusion and poor judgement. Lack of oxygen to the brain for two to eight minutes will cause the eventual death of brain cells, resulting in varying degrees of disability depending on the location and severity of brain damage. 2. The worker shall enter only where all of the appropriate prescriptions of sections 68 and 70 of the regulations for Industrial Establishments have been complied with. Sections 25(2)(a) and (d) of the Act state that "an employer shall, (a) provide information, instruction and supervision to a worker to protect the health and safety of the worker; [and] (d) acquaint a worker or a person in authority over a worker with any hazard in the work and in the handling, storage, use, disposal and transport of any article, device, equipment or a biological, chemical or physical agent." Section 68 of the Regulations for Industrial Establishments states: "Subject to section 70, a confined space shall be entered only where, (a) there is an easy egress from all accessible parts of the confined space; (b) mechanical equipment in the confined space is, (i) disconnected from its power source, and (ii) locked out; (c) all pipes and other supply lines whose contents are likely to create a hazard are blanked off; and (d) the confined space is tested and evaluated by a competent person who, (i) records the results of each test in a permanent record, and (ii) certifies in writing in the permanent record that the confined space, (A) is free from hazard, and (B) will remain free from hazard while any worker is in the confined space having regard to the nature and duration of the work to be performed." Section 70 of the Regulations for Industrial Establishments states: "A confined space in which there exists or is likely to exist, (a) a hazardous gas, vapour, dust or fume; or (b) an oxygen content of less that 18 per cent or more that 23 per cent at atmospheric pressure, and that cannot be purged and ventilated to provide and maintain a safe atmosphere shall be entered only when, (c) all the requirements of section 68 except subclause (d)(ii) are complied with; (d) the worker entering is using suitable breathing apparatus and a safety harness or other similar equipment to which is securely attached a rope, the free end of which is held by a worker equipped with an alarm who is keeping watch outside the confined space; (e) the worker entering is using such other equipment as is necessary to ensure the worker's safety; (f) the safety harness, rope or other equipment mentioned in clause (d) have been inspected by a competent person and are in good working order; and (g) a person adequately trained in artificial respiration is conveniently available."