Young stars burn bright blue because they are at their hottest.
In the process they also expel vast amounts of energy and this clears the area around them.
In the snip below one can clearly see the dust and other nebula material being blown away and dispersed by the newly formed bright star.
Snip taken from here:
Also one can see the resultant cavity and bubble like appearance of the entire nebula.
Hubble Observes Infant Stars in Nearby Galaxy by NASA Hubble Space Telescope, on Flickr