Spectra of the o-CH₂ J = 4 → 3 fine-structure level toward (clockwise from the top-left) W49 N, W43, W75 N, DR21, and S140 observed using the Onsala 20 m telescope. The individual fits to the HFS components are displayed by dotted blue curves while solid red curves display the combined fit. The positions and relative intensities of the corresponding, blended HFS components are displayed below. The dashed blue line in each panel indicates the systemic velocities of the sources.