  We present polarization maps of G30.79 FIR 10 (in W43) from thermal dust
emission at 1.3 mm and from CO J=$2 \to 1$ line emission. The observations were
obtained using the Berkeley-Illinois-Maryland Association array in the period
2002-2004. The G30.79 FIR 10 region shows an ordered polarization pattern in
dust emission, which suggests an hourglass shape for the magnetic field. Only
marginal detections for line polarization were made from this region.
Application of the Chandrashkar-Fermi method yielded $B_{pos} \approx 1.7$ mG
and a statistically corrected mass to magnetic flux ratio $\lambda_{C} \approx
0.9$, or essentially critical.
