CARBON MONOXIDE ACCUMULATION IN CA STORAGES 



G. David Blanpied, Pomology Department 

 Cornell University, Ithaca, New York 



Carbon monoxide (CO) is a colorless, odorless gas which causes 

 numerous deaths each year. Almost all of these deaths are caused 

 by CO in the exhaust from internal combustion engines. Human res- 

 ponse depends upon the concentration of CO and the length of exposure 

 to it. For example, you wouldn't notice 100 ppm of CO if you were 

 exposed for 3 hours, but after 8 hours you would be nauseous and 

 have a headache. CO at 900 ppm would cause the same symptoms after 

 1 hour. Exposure to 4000 ppm of CO would be fatal in less than 1 

 hour . 



The possibility of CO in CA storage was brought to my attention 

 this past spring by Warren Stiles. He reported that workers in 2 

 Maine apple packinghouses had developed headaches and had become 

 nauseous after working in an area adjacent to the door of a newly 

 opened CA room. At both establishments an oxygen burner had been 

 used to reduce the oxygen concentrations in the CA rooms. Analyses 

 of the air in the areas surrounding the newly opened CA rooms revealed 

 the presence of CO at concentrations which could cause CO poisoning 

 symptoms to develop after exposure for several hours. 



We analyzed the atmosphere in 10 Hudson Valley CA rooms that 

 had been "burned" with Anderson, Arcat, and SMB burners at harvest 

 and/or after resealing in the spring. The 5 rooms that had been 

 "burned" in the fall had 50-200 ppm of CO. The 5 rooms that had been 

 recently "burned" after resealing had 250-1800 ppm of CO. 



Early this summer we sealed an empty CA room at Ithaca. With 

 a new catalyst bed in an Arcat the room was "burned" to 3% oxygen. 

 We learned that most of the CO was produced when the oxygen in the 

 room was between 5 and 3t. Also, the faster the flow of propane to 

 the burner, the higher the amount of CO that accumulated in the room. 



The take-home lessons from these observations are clear. If 

 you are lowering the oxygen in a CA ro'om \\fith an open- flame burner, 

 such as an Anderson burner, thoroughly ventilate with fresh air 

 the area adjacent to the discharge from the CA room. When you open 

 a CA room in preparation for removal of apples, ventilate with fresh 

 air the area around the CA door if people will be working nearby. 



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