26 Biosafety Manual • EH&S can assist in determining if a respirator is needed and which type, call (515) 294-5359. • Personnel who are required to use dust masks or other types of respirators for personal protection must participate in annual respirator training and fit testing. Medical approval to wear respiratory protection is required before training and fit testing can occur. More information is available on the Respirator w eb page. • The PI or laboratory supervisor is responsible for conducting hazard assessments, training, and coordinating the use of PPE. Completion of a hazard assessment in association with a standard operating procedure allows individual laboratory PPE requirements to be determined and justified by PIs or laboratory supervisors. Document PPE selection on a standard operating procedure developed for the experiment or laboratory operation. Laboratory Practice and Technique Personnel can be infected with organisms they come in contact with in the workplace. In order for infection to occur, there must be an adequate number of organisms to cause disease (infectious dose) and a route of entry into the body. Knowing how infectious organisms are transmitted and the infectious doses can help in evaluating risk and avoiding infection. Information about the organism(s) must be gathered prior to starting work with them. Safety information about pathogens can be obtained through Pathogen Safety Data Sheets and the BMBL . Infectious agents are transmitted through one or more routes of exposure: • Sharps (parenteral) injuries (needlesticks, cuts with contaminated broken glass, etc). • Inhalation of aerosols (microscopic solid or liquid particles (5 micrometers or less) dispersed or suspended in air). • Ingestion (oral-fecal routes of contamination are a common source of infection; hand-washing is imperative). • Mucous membrane exposure (including the eyes, inside of the mouth and nose, and the genitals). Using work practices that block routes of exposure can prevent workplace infection. Good microbiological techniques must always be used in the laboratory: • Wearing appropriate PPE blocks potential routes of exposure.