No, it's not toxic - unless you eat it anyway. Not specifically "marine" though and doesn't have the international rep like Sikaflex or 3M products. And apparently no advertising. But Canadian Sailcraft boats (I have a CS27) used it for all deck hardware as well as the hull/deck joint. I have no leaks from any original hardware attachments. I also just removed my forward hatch to replace it because it was basically falling apart and not worth the rebuild. It leaked between the acrylic and the frame but the frame/deck attachment with butyl was leak free - after 33 years. The butyl was still flexible as well because it doesn't ever dry out or harden. Needless to say the new hatch will be butyl sealed as well. I'm sure other builders have used butyl as well.
Living aboard in Victoria Harbour
Last edited by mitiempo; 11-22-2010 at 12:10 AM.