If you can smell it, it is not safe to use. Some people said that well aged cedar (that with all sap & aromatic oils leeched out) is tank safe. That means you need to weather the wood for years. At any rate, if you smell cedar, it is not aged enough. <And personally, I wouldn't chance it, smell or no smell!>
80 gal FW with 30 gal DIY wet/dry/sump.
9 fancy golds, 1 hillstream loaches, 1 rubber-lip pleco (C. thomasi), 3 SAEs, small school of white cloud minnows, planted.