  We quantify the consequences of intergalactic dust produced by the first Type
II supernovae in the universe. The fraction of gas converted into stars is
calibrated based on the observed C/H ratio in the intergalactic medium at z=3,
assuming a Scalo mass function for the stars. The associated dust absorbs
starlight energy and emits it at longer wavelengths. For a uniform mix of
metals and dust with the intergalactic gas, we find that the dust distorts the
microwave background spectrum by a y-parameter in the range
(0.02-2)x10^{-5}(M_d/0.3M_sun), where M_d is the average mass of dust produced
per supernova. The opacity of intergalactic dust to infrared sources at
redshifts z>10 is significant, tau=(0.1-1)x(M_d/0.3M_sun), and could be
detected with the Next Generation Space Telescope. Although dust suppresses the
Ly-alpha emission from early sources, the redshifts of star clusters at z=10-35
can be easily inferred from the Lyman-limit break in their infrared spectrum
between 1-3.5 micron.
