Ran across this video just now. I looked up the actual rules:
The number of Hispanic crews in the Northwest has increased markedly in recent years. A count of Spanish surnames on crew rosters suggests that about 85 percent of current contract firefighters are of Hispanic descent. This rough estimate doesn’t indicate how many crew members speak English.
There is no contract requirement that supervisors on contract crews speak any language other than English. There is a requirement that supervisors be able to communicate with the workers for whom they are responsible.
Consequently, if private companies elect to hire crew members who do not speak English, those supervisors must be bilingual or multilingual.
It does look like the forest service is paying attention to this issue and they indicate that no supervisors have been fired for not speaking Spanish.