Emissions tests on US engines and turbines are filed with EPA by retyping the test report by hand. About 1 in 4 filings we checked has a slip.

Slipschecked by hand

18 of 66 filings

A number in a different box, a date slip, settings copied from another job.

Why nowERT filings, last full month

1,695 in Aug 2026

Engine and turbine ERT filings posted on EPA WebFIRE in August 2026, the last full month listed. January 2025 had 20: EPA made online filing mandatory for engines that February, and for turbines in January 2026.

What we doStackbook

Stackbook reads the test report and fills in EPA's form, flagging anything a reviewer would catch.

Plate I · Engine and turbine test filings sent to EPA each month Every filing listed on EPA WebFIRE, Jan 2025 to Aug 2026 (24,773 in all)

02 · Details

The slips, by filings: value in another field or form 4; process value under another parameter 4; setup value carried over from another job 3; date or time slip 3; other 6. As far as we can tell, none changed whether a unit passed.
Reading only the report PDF, Stackbook filled in 190 of the 454 values firms filed. 109 of the rest aren't in the report at all; they come from the firm's own records.
66 public filings with the report attached, one recent filing per firm plus earlier spot checks, Mar 2025 to Aug 2026. Not a random sample. No firm, site or filing is named. This is about the retyping step, not about whether anyone complied.

By: Naman Mishra
Data: EPA WebFIRE public filings, checked October 2026
Index: nl06.com