A chemistry teacher involved in an experiment that badly burned two students at the elite Beacon School on the Upper West Side has been reassigned pending an investigation, officials said Monday.

Anna Poole had hoped to treat her class to a “fun” demonstration of the rainbow of flame that results from burning four kinds of nitrates in separate crucibles.

But the experiment ended in a fireball that engulfed sophomore Alonzo Yanes, 16, and injured Julia Saltonstall, also 16.

Yanes remains hospitalized from the Jan. 2 fire. Saltonstall suffered less severe burns to her neck, head and arm and is back at school.

Poole, 31, has been reassigned and removed from class to a “rubber room” while officials investigate, said an Education Department spokesman.

Students wore no goggles or aprons and were not behind protective glass during the demonstration, sources said.