Chemical safety levels (CSLs): A proposal for chemical safety practices in microbiological and biomedical laboratories

Abstract Microbiological and biomedical laboratories handle chemicals of various hazards in many diverse ways and quantities. Although there are biosafety levels that classify laboratories by the hazard of the biological agent and its use, there are no similar guidelines for classifying chemical safety practices. We propose a system for using chemical safety levels (CSLs) in these laboratories. These CSLs, CSL1 (low risk), CSL2 (moderate risk), CSL3 (substantial risk), and CSL4 (high risk), are classified by the chemical hazards and the nature of the work in which these chemicals are used in the laboratory. Risk at each CSL is governed by limiting or restricting chemical usage or type of work. Standard and CSL specific safe practices, equipment, and facilities requirements are proposed. This work is presented as a starting basis for developing a CSL system, and additional details and modifications will be finalized through a pilot project.