The oxidation related defects in porous n-type 4H-SiC have been studied by electron paramagnetic resonance spectroscopy. Two main centers are observed after a 1000degreesC oxidation in dry oxygen. The first one is isotropic with a g-factor of 2.0028; it is attributed to a carbon related center in the oxide. The second center is anisotropic with C-3v or C-1h symmetries depending on its orientation relative to the c-axis. Its g-factors are g/(/c) = 2.0024 and g(perpendicular toc) = 2.00315 and g(xx) = 2.0031, g(yy) = 2.0028, g(zz) = 2.0023. From its central and ligand hyperfine interactions it is attributed to a Pb like carbon dangling bond center at the SiC side of the interface: (P-bc). The P-bc is electrically active and introduces a deep level. The concentrations of the two defects are estimated to [C] = 10(18) cm(-3) and [P-bC] = 10(12) cm(-2).