The Colorado Air Pollution Control Division - Air Toxics and Ozone Precursors Program (APCD-ATOPs) is seeking a vendor to provide calibration gases for air toxics monitoring. The vendor must be able to produce and recertify specialty calibration gas mixtures to a blend tolerance of +/- 10% and a certification accuracy of +/- 5%. The mixtures must be provided in 150A "SGS" (150 c.f.) aluminum refillable cylinders. The contract is for known regularly purchased gases, but APCD-ATOPs reserves the right to purchase other gases and equipment from the awarded vendor at their standard list price. • The vendor must be able to produce seven different calibration mixtures, each with a specific set of compounds and concentrations. • The vendor must be able to recertify the calibration mixtures to ensure their accuracy and validity. • The vendor must be able to provide the mixtures in 150A "SGS" (150 c.f.) aluminum refillable cylinders. • The contract is for a specific set of gases, but the vendor may be asked to provide other gases and equipment.