Despite  the fact that low metallicity dwarf irregular galaxies
 often  have a paucity of observable CO, they exhibit star formation
 activity  that  can be as high as that found in starburst galaxies.
 Our recent Kuiper Airborne Observatory (KAO) observations, show that
 the  158  micron  [CII]  line  is  bright  and  extended in dwarf
 galaxies.  The [CII] line intensities for the metal poor galaxies
 that  we  have detected with the KAO are 1x10^4 to 6x10^4 times the
 CO(1-0)  line  intensity.   This  effect  is  due  to the decreased
 metallicity  and  dust  content  which  results in reduced CO cores
 surrounded by larger photodissociation regions.  These observations
 suggest that the CO(1-0) line may not be a good tracer of molecular
 gas in these galaxies since H2 may exhist in the [CII] zone.
 The  KAO  is only able to detect a very limited number of dwarf
 galaxies  due  to  its relatively poor sensitivity.  Thus, very few
 metal-poor  low  luminosity  dwarf galaxies have been observed.  We
 propose  to  extend  our  KAO  sample to lower luminosity irregular
 galaxies of varying metallicities with ISO observations of [CII],
 [OI]  and  [NII].  Combined with CO, FIR continuum and 21 cm HI
 measurements,  these  observations  will  allow us to determine the
 physical  conditions of the photodissociated gas in these galaxies.
 For the first time, we will be able to make a complete inventory of
 the gas reservoir in dwarf irregular galaxies where use of CO alone
 to infer H2 may significantly underestimate the molecular mass.  The
 results  of  this  study  will help to address unresolved questions
 about the physical properties of clouds and star formation processes
 in irregular galaxies.