This product is made with bird food quality alpiste and is NOT silica fiber free.

Alpiste - Wikipedia has links to 2 scientific abstracts that link bird food quality alpiste to esophageal cancer onlinelibrary.wiley.com/doi/10.1002/ijc.2910260514/abstract annhyg.oxfordjournals.org/content/38/2/149.abstract

Yes, bird food quality Alpiste is linked to cancer due to the microscopic silica fibers on the seed hull.  Pureza brand silica fiber free alpiste is safe for human consumption.