Guidance for Using Masks in MBL Work Areas

Updated 5/29/21

With narrow exceptions, a face mask covering the mouth and nose must be worn indoors.  A face mask must:

  • Fit snugly around the nose and chin with no large gaps around the side of the face
  • Be secured with ties, ear loops, or headbands
  • Cloth masks must be made of multiple layers of tightly woven fabric that does not let light pass through when held up to a light source.
  • Not include exhalation valves or vents.
  • When working with hazardous materials, disposable masks should be used.  Disposable masks are available for purchase in the MBL Stockroom.

Individuals can remove face coverings if they are in a private room/office alone with the door shut or while eating indoors (including designated breakrooms) or in outdoor tent spaces.

Speakers must wear masks at all times unless in areas marked approved for mask-less speakers. In the instances when speakers are approved to be mask-less they are permitted to remove their masks only when they are speaking to ensure the audience can hear them clearly. This applies to the speaker only. Despite the Commonwealth relaxing indoor mask and distancing requirements for most settings on May 29, 2021, masks continue to be required indoors in all MBL buildings. 

When putting on and taking off a mask, do not touch the front of it.  You should only handle the ties or ear straps.  Also, you should be careful not to touch your eyes, nose, and mouth when removing your mask.  Immediately wash your hands or use hand sanitizer after touching the mask.

Cloth masks should be washed regularly using warm water and regular laundry detergent in a washing machine, or hand washed with soap or hand wash detergent.  After lathering, the mask should sit in hot water for 30 minutes.

If you have any questions or concerns, please contact Eric Jensen (EHS Manager) at 508-289-7424 or by email at

MBL-branded masks can be purchased through the Gift Shop.

See link below for additional information on how to properly wear a cloth face covering or mask.

Mask Guidance for Unvaccinated People