Consequences of Large-scale Production of Marijuana in Residential Buildings

Abstract

Based on the data from the breadth of Canada (∼4300 km), one-third of Canadian homes have ventilation rates below the recommended standard of 0.3 air changes per hour and are at risk for moisture problems. For the purposes of this investigation, a literature review was performed on the health risks associated with exposure to living and drying marijuana plants and the fungi associated with large numbers of indoor plantings. Analysis was made of the impact on Canadian homes if used to grow marijuana. These are commonly called “marijuana grow operations” based on measured ventilation rates from homes in Windsor, Ontario and Regina, Saskatchewan (representing diverse climates) and derived moisture loadings from published data. The growing and drying of marijuana plants contributes considerable amounts of water vapour to the indoor environment. Depending on the scale of production, considerable mould damage in the building can result. There are also a number of abiotic hazards resulting from marijuana production including pesticides, carbon monoxide, and products of unvented combustion appliances. Both indirect and direct evidence are described for the health impact of living in these conditions. This has a number of implications in terms of documentation and personal protection for industrial hygienists, home inspectors, and public health officials.

The Health Risks of Belgian Illicit Indoor Cannabis Plantations

“…and Aspergillus sp., were also identified as the most frequent mold species in illicit indoor cannabis plantations in the USA (7,15) and Canada (5). In Canada, on cannabis flower buds, Aspergillus fumigatus was the most frequently found mold species (5). In their study on 30 indoor cannabis plantations in the USA, Martyny et al (7) further found Cladosporium sp.…”

“…The most frequently found mold species in our study, Penicillium sp. and Aspergillus sp., were also identified as the most frequent mold species in illicit indoor cannabis plantations in the USA (7,15) and Canada (5). In Canada, on cannabis flower buds, Aspergillus fumigatus was the most frequently found mold species (5).…”

Potential Exposures Associated with Indoor Marijuana Growing Operations

“…(2,(4)(5)(6)(7)(8) Many law enforcement agencies, especially in Canada, have indicated that specific PPE must be worn to protect responders entering IMGOs. (2,5,12,13) This study was conducted to identify the hazards associated with IMGOs in Colorado and to suggest appropriate PPE for entry by law enforcement officers..…”

“…Johnson and Miller (6,8) conclude that increased moisture levels in IMGOs likely cause elevated mold spore levels that could be associated with allergic reactions and allergic bronchopulmonary aspergillosis as well as fungal infections. The Institute of Medicine (IOM) and World Health Organization (WHO) have indicated that the presence of mold in damp indoor environments is associated with upper respiratory symptoms, wheeze, cough, asthma symptoms in sensitized individuals, and hypersensitivity pneumonitis.…”

“…(4) In addition, ventilation rates are often suppressed to limit odors emanating from the concealed operation, and irrigation rates are high to maximize production. (3,4,6,7) A study of typical ventilation rates in Canadian housing led Miller and Johnson (6) to conclude that Canadian houses built after 1980 would be at high risk for moisture-and mold-related damage if used as IMGOs.…”