Authorities said Stewart submitted documents that earlier this month he had inspected 19 boilers in Queens when, in fact, he had not.
The arrest followed an investigation that DOI conducted with FDNY's assistance after the FDNY reported the suspected falsified reports.
"This inspector fundamentally breached his professional duty to enforce fire safety rules and maintain truthful records and needlessly risked safety," DOI Commissioner Rose Gill Hearn said.
According to investigators, Stewart claimed he had inspected 14 boilers at the Le Havre building complex on 162nd Street in Queens and the boilers at five other properties on 150th and 154th Streets.
Investigators found that Stewart sat in his car and filled out fraudulent information on the inspection reports without ever looking at the boilers.
Fire inspectors are required to complete these records so buildings owners and management companies can be billed for inspections and receive valid inspection stickers.
A Fire Prevention Inspector is a civilian employee of the FDNY who inspects commercial and multi-family dwellings and enforces the fire code.
Stewart has been employed with the FDNY since October 1999. He has been suspended, officials said.