It depends on the manufacturer. Craft products designed for home use may not be. You’ll generally see a comment like “certified nontoxic when used as directed.” Many commercial products in liquid form are considered “irritants” and can cause mild to severe breathing problems (and potentially asthma) depending on exposure. We recommend that you always wear a breathing mask, gloves to avoid skin contact, and protective glasses to avoid splashes. Many of these resins in liquid form are toxic to aquatic life. However, once cured, they are classified as nonhazardous.