Yes, Klaralyte Salt Capsules are tested for lead and mercury, in addition to testing for many other potentially harmful elements.  Here is a brief overview of the manufacturing process as it relates to ingredient testing:
• Each ingredient comes with a certificate of analysis, which is reviewed prior to and at the time of receiving.
• Each ingredient is tested for purity and product claims at our facility, before production starts.
• Production line is thoroughly cleaned, inspected and tested before production starts, to ensure a pure environment.
• Ingredients are mixed and mix is tested for purity and product claims.
• Final product is tested in-house for purity and product claims, and a certificate of analysis for the lot number is produced.
• Random sample lots are independently tested for purity and product claims.