I personally don't have these for my daughter - prefer wooden toys myself. The US Consumer Product Safety Commission have re-called MAGNETIX toys by the company Rose Art \link{http://www.news10.net/storyfull2.aspx?storyid=16769\news 10 abcnet article}
This came to my attention through a blog I read, Hsien Hsien Lei's Play Library www.playlibrary.com/2006/03/31/magnetix-toy-recall/#comments and I've listed it on my own blog here www.reallifecalling.blogspot.com/
The US Product Safety Commission have recalled the product because:
"Hazard: Tiny magnets inside the plastic building pieces and rods can fall out. Magnets found by young children can be swallowed or aspirated. If more than one magnet is swallowed, the magnets can attract to each other and cause intestinal perforation or blockage, which can be fatal. This product is unsuitable for young children.
Incidents/Injuries: CPSC is aware of 34 incidents involving small magnets, including one death and four serious injuries. A 20-month-old boy died after he swallowed magnets that twisted his small intestine and created a blockage. Three children ages ranging from 3 to 8 had intestinal perforations that required surgery and hospitalization in intensive care. A 5-year-old child aspirated two magnets that were surgically removed from his lung
Please be warned and take action