apple incorporated several features in the design of the macbook air, such as the reduction of toxic chemicals like lead, to make it more environmentally friendly. macbook air contains no bfrs and pvc wiring, meets energy star version 5.0 requirements, has a recyclable enclosure, and is rated epeat gold; its screen is made from arsenic-free glass and does not contain mercury. to reduce the computer's size and weight, several features were sacrificed. it is apple's first notebook since the powerbook 2400c without a built-in removable media drive. it also omits a firewire port, ethernet port, line-in, media card slots, and a kensington security slot.