Rodent and Pest Control Program for Medical Device Manufacturing

There are no direct requirements regarding pest control in ISO 13485:2016. However, in requirement 6.4 Work environment is stated that the manufacturer must document the requirements for the work environment if the conditions for the work environment can have an adverse effect on product quality. Therefore, if the appearance of pests can affect the quality of the product, then it is definitely necessary to conduct pest control.  

I recently audited a company that allowed insecticides to be sprayed in the warehouse and production area.  Unless they are performing rework, all materials remain within sealed primary or final packaging.  This still does not seem right to me but I cannot find any regulation to back me up.  Any thoughts?

There is no strict regulation regarding spraying the warehouse area. It is mostly defined locally. The company that provides Pest control must first make a risk assessment and an explanation of the Pest control measures that will be implemented in one company. Therefore, in that document, there should be a justification for why it is acceptable to carry out spraying as a method of protection against insects.