Why is Wilson covered with dust from the ashes?

Answer 1

The ashes that cover Wilson are from the soot produced from the factories that surround where he and Myrtle live. It symbolically represents the fact that he and Myrtle are stationary, unmoving, and, one would even argue, dead. From another angle, it could be argued that the ashes represent how the rich (who run the factories) abuse the poor.

Answer 2

Wilson is covered in dust from the ashes due to the volcanic eruption that occurred on the island where Chuck Noland, played by Tom Hanks, is stranded in the movie "Cast Away." The volcanic ash covered the entire island, including Wilson the volleyball, which is why he appears dusty.