A team of researchers from three universities including the Illinois Institute of Technology, recently published a Journal regarding emissions from 3D Printers concerning about health hazards of 3D Printing. PLA filament emitting lactide bits and ABS filaments emitting Styrene were worth concerning, however, the exposure levels need to be high enough for them to be effectively harmful.
Source: http://www.digitaltrends.com/cool-tech/3d-printing-health-hazards/