OSHA has made revisions to its standard 29 CFR 1910.1450, Occupational Exposure to Hazardous Chemicals in Laboratories. The agency says the changes highlight significant developments in laboratory practices. Key revisions include guidance for designing a hygiene plan for laboratories using hazardous chemicals. This addresses hazards of working alone in laboratories; guidelines for working safely with nanoparticles; an emphasis on physical hazards in laboratories such as machinery and equipment; emergency planning and security; and development of a safety culture in laboratories.