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Identifying the astrophysical sites of the $r$-process, one of the primarymechanisms by which heavy elements are formed, is a key goal of modernastrophysics. The discovery of the brightest gamma-ray burst of all time, GRB221009A, at a relatively nearby redshift, presented the first opportunity tospectroscopically test the idea that $r$-process elements are producedfollowing the collapse of rapidly rotating massive stars. Here we presentspectroscopic and photometric $\textit{James Webb Space Telescope}$ (JWST)observations of GRB 221009A obtained $+168$ and $+170$ rest-frame days afterthe initial gamma-ray trigger, and demonstrate they are well-described by asupernova (SN) and power-law afterglow, with no evidence for an additionalcomponent from $r$-process emission, and that the SN component stronglyresembles the near-infrared spectra of previous SNe, including SN 1998bw. Wefurther find that the SN associated with GRB 221009A is slightly fainter thanthe expected brightness of SN 1998bw at this phase, concluding that the SN istherefore not an unusual GRB-SN. We infer a nickel mass of $\approx0.09$M$_{\odot}$, consistent with the lack of an obvious SN detection in theearly-time data. We find that the host galaxy of GRB 221009A has a very lowmetallicity of $\approx0.12$ Z$_{\odot}$ and our resolved host spectrum showsthat GRB 221009A occurred in a unique environment in its host characterized bystrong H$_2$ emission lines consistent with recent star formation, which mayhint at environmental factors being responsible for its extreme energetics.

JWST Observations of the Extraordinary GRB 221009A Reveal an Ordinary Supernova Without Signs of $r$-Process Enrichment in a Low-Metallicity Galaxy