SINAK Corporation is proud to announce that our clear concrete treatments submitted for certification have passed a rigorous and thorough testing process and are GREENGUARD Indoor Air Quality Certified. SINAK Corporation has been a leader in the industry since 1979 with its unique line of proven, environmentally friendly treatments for concrete. Continue to the website to print GREENGUARD certificates. These certificates have been approved by the USGBC to be used for LEED project submissions as proof of the certification.