Silica gel packets are designed to absorb moisture, and are often packaged with electronics and other various products. They typically function as a kind of desiccant and absorb moisture that might otherwise harm the product they are packaged with. This may seem like a dangerous thing to ingest, though it isn't necessarily the moisture-eliminating nature of these packets that can make them dangerous. The potential danger typically lies in poisonous dopants that are sometimes used to dye some, or all, of the silica beads inside the packets. One such dopant is cobalt dichloride, which is a blue substance that will turn pink in the presence of moisture. If a silica gel packet contains poisonous dyes like these, then they can be dangerous.
Conventional wisdom may indicate that ingesting a moisture-absorbing substance could be quite dangerous, but the amount contained in typical silica packets generally isn't enough to do any harm to either humans or pets. Silica gel by itself is non-toxic and, if a child or animal ingests some, they will often be fine. Silica gel packets may present a choking hazard, so close observation should be maintained and medical assistance sought if choking occurs. Otherwise, the main danger typically comes mainly from poisonous additives.
In order for the packets to be most effective, it can often be useful to know if the silica gel has absorbed any moisture. To this end, dyes that change color in the presence of moisture are often added to some, or all, of the silica beads. One of the common dyes, cobalt dichloride, is a carcinogen that should not be ingested. If it is suspected that a child or animal has ingested a large amount of sodium dichloride, it may be wise to immediately contact poison control or other health professionals.
Silica gel packets may use a non-toxic moisture indicator. While cobalt dichloride is a blue substance that will turn a rose, or pink, color in the presence of moisture, other non-toxic agents will typically start out orange and turn green after absorbing moisture. Ingesting silica gel that has been dyed with additives like these may be less inherently dangerous, though it may still be a good idea to alert poison control.
Silicosis is a condition that can be caused by the inhalation of silica dust, but this is not a concern typically associated with silica gel packets. The beads in the packets generally have a different physical construction from the kind of dust that causes silicosis. So, while inhaling beads from a silica gel packet may often produce irritation and require medical assistance, there is little to no danger of contracting this condition.