When procedures change, stop and reassess the risk.

When to Stop and Reassess the Risk Certain indicators (e.g., procedural changes) should cause the employee to stop and review the safety aspects of their procedure — even if it is a familiar procedure. Hazards may then exist that are not fully recognized. These indicators include: New procedures, processes or tests even if they are very similar to older practices. A change or substitution of any of the ingredient chemicals in a procedure. A substantial change in the amount of chemicals used (scale-up of experimental procedures); usually one should review safety practices if the volume of chemicals used increases by 200%. A failure of any of the pieces of equipment used in the process, especially safeguards such as chemical fume hoods. Unexpected experimental results (such as a pressure increase, increased reaction rates, unanticipated by-products). When an experiment's result is different from the predicted, a review of how the new result may affect safety practices should be made. Chemical odors, illness in the laboratory staff that may be related to chemical exposure, or other indicators of a failure in engineered safeguards. The occurrence of any of these conditions should cause the researcher to pause, evaluate the safety implications of these changes or results using the risk assessment process, make changes as necessary, and proceed cautiously. If needed, call the Occupational Health and Safety Section for assistance.