VOC's (volatile organic compound) are mostly found in paints and glues. Ceramic / porcelain tile with thin set contains no VOC's. Neither does any natural stone counter top material (like granite). Man made 'stone' is really crushed rock glued together with an epoxy like binder. Besides - the VOC's evaporate and disburse into the atmosphere. They don't stay in your home.

jdesign_gw: When you miter or rabbet veined material, you lose the thickness of the saw blade from the pattern, known as saw "kerf". The only way to keep that loss to an absolute minimum is to miter on a V-grooving machine. No matter how a sintered edge is made, it must be profiled at least minimally. That minimum will cut through the "picture" on the top and expose the un-veined material.

I have found that much of the advice from appliance manufacturers regarding flush, inset, and other unusual appliance installation applications is completely wrong. There is usually no engineering analysis done vetting these unusual installations. Often the advice manufacturers give is actually dangerous. Such as advising until 2011 using high CFM hoods with professional appliances in homes without replacement air systems. Manufactures knew this was dangerous for a decade before building code was changed to protect consumers. Insetting ovens in inset and beaded inset cabinetry is crazy and very dangerous, but it is presently encouraged by appliance manufacturers because home owners like the look. Our company will not sell a kitchen with these fire hazard applications, and we have lost 40 and 50K cabinet orders because we refuse to sell it. That being said I would guess that the gap around the cooktop with a Deckton top would be needed for expansion and not for venting, and that your gap looks about right. I have no idea if high temperature silicon will hold up over time but it can easily be removed. And the application at least doesn't seem dangerous. High-temperature silicone is designed to withstand up to 500°F, but some formulas are rated up to 572°F or 600. I doubt any countertop fabricator will remake a top at no charge with this unusual appliance application. But I think it isn't needed and that you already have the best case scenario. If it cracks as Joseph says due to the tight radiuses then you can ask them to replace it at no charge and get larger radiuses, or better yet install the cooktop the way it was designed for. As a top mount.

Like all the sintereds, mighty tough to fix if you break it. If this were Corian, it would fix inconspicuously, but then if it were Corian, it wouldn't have broken in the first place. If it can't be repaired, needs to be replaced, and your color is discontinued, you'll replace all the tops, even the undamaged.