As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT GATE, SMOKE BEGAN TO FILL CABIN AND HEAVY SMOKE WAS ALSO OBSERVED COMING FROM RIGHT WHEELWELL AREA. APU SHUT DOWN AND SMOKE CEASED TO ACCUMULATE. PASSENGERS DEPLANED. MAINTENANCE FOUND GLYCOL IN AND AROUND APU EXHAUST DUCT. GLYCOL WAS REMOVED. APU OPERATED NORMALLY.