THE District of Columbia Fire Department's recent assault on Metro, charging fire hazards in the subway cars, is decidedly strange. It's the same fire department that took part in the discussions of subway design, that proposed changes in materials and that saw those changes adopted. Now, it's attacking the standards that it earlier helped write. What's going on here?

Part of the explanation is a change of command within the fire department, evidently reawakening an internal quarrel over Metro standards. But this sudden change of position also has a lot to do with an accumulation of disputes over safety among Metro and the region's local governments. Douglas Feaver describes the issues in an illuminating article on the opposite page.

The specific objection raised by city fire department officials is not persuasive. They argue that the seats and interiors of the subway cars might, under certain circumstances, burn or smoulder and emit toxic fumes. That's true. At sufficiently high temperatures, almost anything will burn or emit toxic smoke. The fire department's current alternative, stark metal interiors and metal seats, is unappealing. It would impose a grim jailhouse decor on Metro, and it's not at all clear that there would be any improvement in safety. Elimination of a small residual risk of fire might well be offset, and worse, by the higher risk to injury to passengers from hard metal edges in cases of sudden stops, let alone collisions.

A long process of discussion, review and revision of standards had given Metro attractive and comfortable cars with an extremely low likelihood of fire. The fire danger is not zero. But Metro has struck a reasonable balance. For the fire department to pursue a campaign against standards that it helped to write, under which millions of dollars have now been spent, would be irresponsible.

But the firemen's uneasiness about Metro is clearly -- and properly -- being fed by a realization that their present state of training for underground emergencies is inadequate. They are uncertain that they could evacuate a train quickly in case of fire or any other necessity. The right response by Metro is not to fiddle with seat fabric, but to undertake, with firemen and rescue squads, thorough and realistic preparation for any crisis underground.