Identify and assess risk by finding out what chemicals are in use (check the SDS and label, check whether there is an exposure standard, consider all routes of exposure), considering the work (observe tasks and practices, conditions, what could go wrong such as spillage, review incident information) and assessing risk (how long and how often workers are exposed, whether controls match the label and SDS, pre-existing medical conditions, health monitoring). Example controls include negative pressure rooms, good ventilation such as extractors, fume hoods and plume evacuators, safe dedicated storage (compressed gas cylinders preferably outdoors in a secure shaded cage and indoors only in a purpose-designed building with fire-rated walls and ventilation), following exposure standards, health monitoring, a register with SDS, monitoring chemicals with standards including in storage in case of leaks, closed systems for cleaning scopes with peracetic acid, signs, labelling, rotating staff, and fit-fitting PPE such as fit-tested P2 or N95 masks. Chemicals can react with each other so read the SDS and label for separation. In the in-home case a provider surveyed workers, found household cleaners not on the register, obtained SDS, assessed shower and oven cleaning, kept SDS in clients' homes and in the office and asked workers to open windows, use exhaust fans and wear gloves, and stopped using products without the manufacturer or importer's label.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.