Evaluation of the use of ProFume® fumigant (sulfuryl fluoride) on dried/cured tobacco leaf in storage facilities

Abstract: Due to the increasingly high levels of phosphine resistance observed in field
populations of the cigarette beetle (Lasioderma serricorne L.), there has been increased interest by major tobacco producers, including R. J. Reynolds (subsidiary of British American Tobacco Group), to find alternative treatments for control of cigarette beetle. In 2019, a study was conducted to determine the penetration, distribution, and aeration properties of ProFume® gas fumigant (99.8 % sulfuryl fluoride) when treating C48 cartons of compressed dried/cured tobacco for cigarette production. Residue analysis of treated and untreated tobacco from this study was conducted. Sulfuryl fluoride was found to fully penetrate into C48 cartons of compressed tobacco 1.6 hours post-introduction when the first measurement was obtained. No statistical differences were detected between fumigant concentrations or accumulated dosages obtained in the perimeter and core of cartons. Differences were detected within cartons at various sample times within individual tarped stacks with upper cartons having lower concentrations of fumigant than lower cartons. This was determined to be due to application methods and a later study conducted in 2020 resolved this issue. Aeration for all but the bottom C48 cartons was completed within 23.5 hours. However, at the next reading, 37 hours postinitiation of aeration, all cartons were confirmed to be 1 ppm or less by both core and perimeter sampling. No sulfuryl fluoride residues were found in any treated or untreated sample. Fluoride, a naturally occurring element, was found in all treated and untreated samples. A smoke panel run by R. J. Reynolds confirmed that experienced smokers could not consistently distinguish between cigarettes made from treated vs. untreated tobacco. As a result of these studies, label language has been developed to permit the use of ProFume to directly treat dried/cured tobacco for cigarette production.