Two alternative chemical methods of atomic iodine generation for a chemical oxygen-iodine laser (COIL) were studied. These methods are based on fast reactions of gaseous hydrogen iodide with chemically produced chlorine or fluorine atoms.Both processes were studied first in small-scale reactors. A yield of atomic iodine in the Cl system and nitrogen (nonreactive) atmosphere exceeded 80%, while in the F system it was only up to 27% related to F2 or 50% related to HI. The process of atomic iodine generation via Cl atoms was employed in operation of the supersonic COIL. A laser power of 430 W at 40 mmol Cl2/s, and the small signal gain up to 0.4 %/cm were attained. The proposed methods promise an increase in laser power, easier control of laser operation, and simpler iodine management in comparison with the conventional source of atomic iodine using 12. The experimental results obtained so far with this experimental arrangement did not proved yet increasing COIL chemical efficiency because some process quenching a part of singlet oxygen was indicated. Therefore a modified experimental set-up has been designed and prepared for further investigation.