(1) The commissioner shall provide for the inspection and analysis of pesticides being used and for the inspection of equipment, devices that require licensure for use, or apparatus used for the application of pesticides, and the commissioner may require proper repairs or other changes before further use.

(2) The commissioner, upon his own motion or upon the complaint of any person, may make any and all investigations necessary to insure compliance with this article.

(3) Complaints of record made to the commissioner and the results of his investigations may, in the discretion of the commissioner, be closed to public inspection, except to the person in interest, as defined in section 24-72-202 (4), C.R.S., or as provided by court order, during the investigatory period and until dismissed or until notice of hearing and charges are served on a licensee.

(4) At any reasonable time during regular business hours, the commissioner shall have free and unimpeded access upon consent or upon obtaining an administrative search warrant:

(a) To any land, water, or structures thereon in which any devices that require licensure for use, pesticides, containers, rinsates, or other related materials are or have been kept, used, stored, handled, processed, disposed of, or transported for the purpose of carrying out any provision of this article or any rule made pursuant to this article;

(b) To all records required to be kept and may make copies of such records for the purpose of carrying out any provision of this article or any rule made pursuant to this article.

(5) The commissioner shall have full authority to administer oaths and take statements, to issue subpoenas requiring the attendance of witnesses before him and the production of all books, memoranda, papers, and other documents, articles, or instruments, and to compel the disclosure by such witnesses of all facts known to them relative to the matters under investigation. Upon the failure or refusal of any witness to obey any subpoena, the commissioner may petition the district court, and, upon a proper showing, the court may enter an order compelling the witness to appear and testify or produce documentary evidence. Failure to obey such an order of the court shall be punishable as a contempt of court.