Warning: don't step into the old cannery off Route 9 in Everett without a dust mask
I poked around the old cannery on Route 9 in Everett last month and the dust was so bad my chest hurt for two days. What worked was a cheap $3 painter's mask from the hardware store plus duct tape over the vents. If you go, bring that and a flashlight, because the floors past the loading dock are soft. Has anyone else run into buildings where the air itself was the real hazard?