It’s something you see on the news more frequently, toxic spills that force a sort of quarantine where people are instructed to stay in their homes in rooms with very little ventilation. This is called shelter in place and for landlords and property managers it’s an interesting situation.
Property owners are expected to cooperate with public officials by letting people take shelter in place on their property. For landlords who own businesses this may be more challenging as the accommodations are not as homey as they would be in an apartment building. But even in an apartment situation the property owners are expected to take in all visitors, employees and others who happen to be on the premises.
Once you get a notice of shelter in place you should inform everyone and ask that they stay, although you cannot force them to stay. Lead them to the predefined safe places and bring any disaster supplies. Plastic sheeting, tape and garbage bags are extremely useful as they can block air leaks and prevent toxic fumes from entering the space.
Shelter in place orders rarely last for more than a few hours. If a chemical spill is especially large or toxic government officials will evacuate an area so shelter in place is really only for smaller contaminants.