The Collaborative International Dictionary of English v.0.48:

lead-free \lead-free\ adj.
   1. not containing the element lead.
      [WordNet 1.5]

   2. specifically: Not containing a lead additive such as
      tetraethyllead or tetramethyllead; -- of gasoline; as,
      Most modern cars run on lead-free gasoline. Oposite of
      leaded.

   Syn: nonleaded, unleaded.
        [WordNet 1.5]

   3. specifically: Not containing a pigment having lead as a
      component; -- of paints; as, lead-free paint should be
      used wherever children are exposed to the painted surface.
      [PJC]

WordNet (r) 3.0 (2006):

lead-free
    adj 1: (of gasoline) not containing tetraethyl lead; "lead-free
           gasoline" [syn: lead-free, nonleaded]