It is also not "innocuous." Inhaling the spray can be at best irritating, 
at worst, it can bring on chemical pneumonia.  
On Tue, 5 Apr 1994 Ctcreel@top.cis.syr.edu wrote:
> Safer Spray is nothing more than glorified soap.  It doesn't kill the
> aphids, just makes the plant less tasty.  It is actually quite effective
> in keeping the aphids away and is completely innocuous to the plants
> and their mammalian keepers.
> 
> I use this stuff at full strength and have never had any ill effects.
> 
> Chris
>