As we do not use any fire retardants (chemical-based fire barrier), we use a glass fiber lining which is federally approved to be used as a fire barrier for memory foam products. The outer cover is not meant to be removed to avoid access to the glass fiber lining. If the cover does get dirty, we recommend spot-cleaning the affected area. As long as you do not remove the cover, the lining is not harmful to your health.
We understand that you may still have concerns regarding your mattress though so please contact us and we would be happy to answer any questions that you may have. -Zinus Please contact us by submitting a ticket at support.zinus.com or call us at (800) 613-1225