Evidence shown on this graph [see website] forms part of the extensive proof that gaseous poisoning is the single cause of cot death. These statistics refute every proposition that SIDS has a medical or physiological cause. When parents/guardians re-use unwrapped baby mattresses, this re-use increases the effects of SIDS...cot death (crib death). If a mattress contains any of the elements phosphorus, arsenic, or antimony, and if certain common household fungi have become established in the mattress during prior use, any generation of toxic gas commences sooner and in greater volume when the mattress is re-used. http://www.sids-prevention-baby.com/graph-on-SIDS.html