Festering Blast question

Not sure about how the Festering Blast spell is supposed to work... It says that the spell has a duration of one minute... Does this mean that the Line cast is maintained for a minute? If so, that's a little broken. The description is a little confusing.

The line occurs at the time of casting. Anyone who fails their save against it takes damage and is poisoned for the duration, taking additional damage each turn until they either save against the poison effect at the end of their turns or the ten rounds end.

Single burst. Potential recurring poison.