Across the 53 companies in the ranked assignee list, filing is concentrated at the top: the leading assignee holds 30 records, and the top 5 combined account for 86 records, or 48.6% of the 177 total in scope. The tenth-ranked assignee holds only 7, showing a steep drop-off after the leaders. This concentration means a newcomer’s freedom-to-operate analysis should start with the handful of top filers rather than the full ranked list.

The complete three-year window from 2021 to 2024 shows filings dropping from 5 to 1, an 80% decline, and the peak year across the whole dataset was 2018 at 23 filings. However, publication typically lags filing by around 18 months, so the 2025 and 2026 figures in this dataset are undercounted and should not yet be read as a continued decline. A fair read is that filing has cooled from its 2018 peak, with the most recent trend still uncertain.

Material analysis and testing (IPC class G01N) covers 58.8% of the 177 records in scope, making it by far the largest category — most of that reflects personal sampler and exposure-monitoring claims rather than suppression methods themselves. Suppression-chemistry materials (C09K) sit at 18.6% and chemical/physical separation processes (B01D) at 13.6%. Mine safety and ventilation equipment specifically (E21F) is comparatively thin at 11.3%, which is notable given the topic’s name.