Producer gas is a fuel gas manufactured by blowing air and steam through an incandescent bed of coke or coal. The primary chemical reactions produce carbon monoxide (CO) and hydrogen gas (H₂). However, the air introduces a large amount of non-combustible nitrogen gas (N₂), which makes up a significant portion of the final mixture.

The composition is approximately:

$\mathrm{CO}:25\%,H2:10\%,N2:65\%$

Therefore, the main components are carbon monoxide and nitrogen gas.

Final Answer: carbon monoxide and nitrogen gas