The California Department of Public Health (CDPH) revised its definition for what constitutes a “close contact” for purposes of Cal/OSHA’s Emergency Temporary Standard (ETS).[1] The revised definition will likely be good news for big box retailers, large manufacturers and warehouses. The rest of the state will remain bound by the existing standard.

As a reminder, this summer, the CDPH defined “close contact” to be an individual who shared the same “indoor airspace” with a person who is infected with COVID-19 for a cumulative total of 15 minutes or more over a 24-hour period. The new definition creates two standards for “close contact” and clarifies what is a shared indoor airspace. According to the new definition:

  1. In indoor airspaces 400,000 or fewer cubic feet per floor (such as home, clinic waiting room, airplane, etc.), a close contact is defined as sharing the same indoor airspace for a cumulative total of 15 minutes or more over a 24-hour period (for example, three separate 5-minute exposures for a total of 15 minutes) during an infected person’s (confirmed by COVID-19 test or clinical diagnosis) infectious period.
  2. In large indoor spaces greater than 400,000 cubic feet per floor (such as open-floor-plan offices, warehouses, large retail stores, manufacturing plants, or food processing facilities), a close contact is defined as being within six feet of the infected person for a cumulative total of 15 minutes or more over a 24-hour period during the infected person’s infectious period.

In other words, if your workspace meets the “large indoor space” definition, merely sharing airspace no longer counts as being a close contact; the individuals must also be within six feet of each other.  That should ease the burden on sending people home after a potential workplace exposure. 

Even though the new Health Officer Order includes “open-floor-plan offices” as an example of a large indoor space, you will not qualify for the more lenient test if your space is not, in fact, greater than 400,000 cubic feet. So, it’s time to brush up on middle school math and remember, the formula for the volume of a cube or rectangular prism (that’s prism . . . not prison) is:

Length x Width x Height. 

Those of you with far more architecturally interesting spaces – round or triangular shapes, for example – will have to brush up on the formulas for triangular prisms and cylinders.    

You are probably generally familiar with Length x Width. That is what real estate people usually market as a building’s square footage. You might need to get out a tape measure to check your ceiling height because frequently, lease descriptions refer to the height from one floor to another, but with features like drop ceilings, the actual height of the airspace could be materially less. If you know the square footage and the height of the ceiling, calculating cubic feet should be easy. But this is California . . .

The CDPH rule specifies spaces separated by floor-to-ceiling walls (offices, conference rooms, bathrooms, closets, etc.) must be considered as distinct indoor airspaces. Employers with enough gross square footage and high enough ceilings may yet be disqualified from the more lenient rule after subtracting the volume of the separate spaces. Having done the math for Squire Patton Boggs’ open-space San Francisco office, I found that the cubic volume of our entire floor only amounted to about 189,000 cubic feet – and that was before subtracting out the separate enclosed spaces. If your space is too small to use the new rule, know that you will be in good company.

[1] Order of the State Public Health Officer Beyond Blueprint (