Duplication of windows Environment Variables

Question

When i try to add PATH variable existing path variables are duplicating.

Below command I am using to add the system variables permanently.

reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /f /v PATH /d "%PATH%;C:\BuildTools;

Here existing path variables duplicating, after that new one is appending.

any solution to avoid this?

Thank you!