Simmons Kids has recalled 20,000 crib mattresses because they are smaller than the required 27 1/4 inch width required by law. This can cause a gap which can entrap a child. The company has one report of an entrapment; the parent was able to free the child.
The recall release gives specific information for measuring the mattress. You should not be able to fit more than two fingers between the mattress and the side of the crib.
If you have this mattress, discontinue use immediately and contact Simmons Kids for a free replacement. There is information on the Simmon's website, or you can call 1-800-810-8611. If you are using another crib mattress that is too small, discontinue its use and report it to the Consumer Product Safety Commission.