Colo. Rev. Stat. § 31-10-1503
Any person violating any provision of this article is a competent witness against any other such violator and may be compelled to attend and testify upon any trial, hearing, proceeding, or investigation in the same manner as any other person, but the testimony so given shall not be used in any prosecution or proceeding, civil or criminal, against the person so testifying except for perjury in giving such testimony. A person so testifying shall not thereafter be liable to indictment, prosecution, or punishment for the offense with reference to which his testimony was given and may plead or prove the giving of testimony accordingly in bar of such indictment or prosecution.
C.R.S. § 31-10-1503
This section is similar to former § 31-10-1303 as it existed prior to 1975.