@willcfc Yes, sintra is the one that has the chlorine. Sintra is just expanded PVC board.
BTW, an inline squirrel cage can be dangerous. See the post Glowforge hooked up to Exterior Dust Collector and my sketch on how to prevent fumes from leaving the squirrel cage housing. I thought I would have no exhaust problems with an inline squirrel cage fan, and quickly learned otherwise!