Dear J.,
When you speak of "bumper around your son's crib" I assume you mean the cloth bumper pads commonly used around the inside of the crib.
As a child care professional for many years I have had many hours of safety training in the field of Early Childhood Care. In correlation with the "Back to Sleep" (SIDS) campaign American Academy of Pediatrics now recommends that nothing be placed in a crib w/a baby with the exception of a thin blanket (like a receiving blanket). I no longer use bumper pads but in the past I have used bumper pads, then removed them right about 6-8 months when the children start becoming more mobile. As explained to us in training there have been strangulation and suffocation cases where children have died as a result of bumper pads being loose or worn when children have gotten their heads stuck under them or injured from stepping on the pads to climb over the railing and fall to the floor.
To ensure his safety my suggestion would be that you remove the bumper pads.
Hope you find this helpful. For other safety questions you may wish to consult your pediatrition or the American Academy of Pediatrics website.
For the Love of Children,
D.
A little about me:
Mother of 2 ages 16 and 19, Early Childhood Professional, specializing in Infant/Toddler care and education for 21 years. Awesome, supportive husband, married 20 years.