The risk of multiple uses of respirator gas filters (literature review)

Abstract

If a worker uses filtering respirators to protect against toxic gases, the cartridges must be replaced promptly, as they have a limited service life. If the service life exceeds the length of the job, the cartridges can be reused in some cases. However, toxic substances can desorb and migrate during storage; and then be released into the inhaled air. So, the cartridges can become a source of hazard themselves. The risk depends on the properties of gases, cartridges, and the conditions in the workplace and during storage. The sensory response to inhaled gas has proven to be an unreliable indicator of the end of service life, and its use has been prohibited. We prepared this article using the results of a search for relevant information in Journal of the ISRP; publications of National Institute for Occupational Safety and Health, U.S. Occupational Health and Safety Administration (OSHA), Taylor & Francis, Springer, Oxford University Press; western law requirements for respiratory protection, and textbooks. The article describes the results of studies of gas desorption during cartridge storage. Researchers have found that hazards can occur when protecting against organic compounds with different boiling points and some inorganic substances. A significant difference is shown between the amount of available information and the possible reuses of the cartridges. There are different ways to protect workers: prohibit the reuse of cartridges when protecting against most hazardous substances; prohibit reuse without the permission of the cartridges manufacturers; limit the duration of their use. If the service life is long enough, the cartridges may be used within their limits (including breaks for storage). Mathematical modelling for risk assessment is described, and recommendations for improved training and workers protection are provided. If a worker uses filtering respirators to protect against toxic gases, the cartridges must be replaced promptly, as they have a limited service life. If the service life exceeds the length of the job, the cartridges can be reused in some cases. Nevertheless, toxic substances can desorb and migrate during storage; and then be released into the inhaled air. So, the cartridges can become a source of hazard themselves. The risk depends on the properties of gases, cartridges, and the conditions in the workplace and during storage. The sensory response to inhaled gas has proven to be an unreliable indicator of the end of service life, and its use has been prohibited. The article describes the results of studies of gas desorption during cartridge storage. Researchers have found that hazards can occur when protecting against organic compounds with different boiling points and some inorganic substances. A significant difference is shown between the amount of available information and the possible reuses of the cartridges. There are different ways to protect workers: prohibit the reuse of cartridges when protecting against most hazardous substances; prohibit reuse without the permission of the cartridges manufacturers; limit the duration of their use. If the service life is enough long, the cartridges may be used within its limits (including breaks for storage). Mathematical modeling for risk assessment is described. Conclusion. Recommendations on improving the protection of workers have been given. They include: improvement of respiratory approval requirements, development of the law requirements for their use, training of occupational health and safety specialists and workers.