Chemical Hygiene Plan Yale University's compliance with each of OSHA's Laboratory Standard elements is detailed in it's Chemical Hygiene Plan. This Plan describes the hazards of chemicals that may be present in your laboratory, and the appropriate work practices, procedures, and controls that should be in place to protect you and other laboratory staff from those hazards. A copy of the OSHA standard and an official copy of the Yale University Chemical Hygiene Plan are available in these locations.