Based on the fact that the company consists of first responders, I believe that this policy is legitimate. That is, it was not designed to save the organization money or otherwise take advantage of the employees. It was designed to protect the people served by the organization.

What you don't say is for how long your husband was sent home and/or if there is testing or otherwise a way for him to be proven well and able to return to work. If he was sent home for a very short period, it would be a different burden than if he was sent home for a longer period of time.

The company should include in its policy requiring exposed individuals to leave work whether these people may/may not/should/should not apply sick time to be paid for absences caused by this circumstance as well as clear guidelines for returning to work.

Remember, too, that normally paid sick time is a gift from the company to the employee. That is, it is not actually earned nor does the law require that a company pay people when they are not working.

If your husband is in a unionized environment, that would be a different matter and the union would weigh in on the situation. If he is an exempt employee under the Fair Labor Standards Act, he should be paid for the entire day if he works any part of it, as a general rule. Hope this is helpful.