GND PERSONNEL AND ADDITIONAL BAGGAGE TO AN EMB145 AFTER PUSHBACK; WITH BOTH ENGS RUNNING.

Narrative

WE WERE PUSHING BACK AND IN CONTACT WITH RAMP CTL. I WAS TOLD I WAS CLRED TO START AND STARTED ENG #2 IN THE PUSHBACK. AFTER THE PUSH; THEY DISCONNECTED AND I STARTED ENG #1. AFTER IT WAS STARTED; I OBSERVED A RAMP PERSON WAVING 1 FINGER AT ME AND POINTING TO ENG #1. I THOUGHT HE WAS INDICATING THAT I WAS OK TO START ENG #1. IT WAS ALREADY STARTED. HE THEN POINTED AGAIN TO ENG #1. UNABLE TO COMMUNICATE; THE HEADSET WAS ALREADY DISCONNECTED; I CONTACTED RAMP ASKING IF THEY SAW A PROB OR IF THEY KNEW WHAT WAS GOING ON. ABOUT THAT TIME THE BAGGAGE DOOR OPENED AND HE CAME BACK AND SAID THAT THEY HAD A LAST MIN BAG AND WERE PUTTING IT ON. IT IS OBVIOUS THAT THEY SHOULD NOT HAVE OPENED THE BAGGAGE DOOR WITH THE ENG RUNNING; IT WAS TOO LATE TO STOP THEM; PLUS THE PAPERWORK WAS ALREADY FINALIZED. I REMINDED THEM TO MAKE THE APPROPRIATE CHANGE ON THE PAPERWORK; BUT I HAVE NO IDEA IF THIS OCCURRED. MY MAIN CONCERN IS THAT THE SAFETY OF THE RAMP PERSONS AND ACFT WERE JEOPARDIZED FOR 1 BAG. ADDITIONALLY; I WAS NOT ALERTED VERBALLY ABOUT WHAT WAS HAPPENING. IN CONCLUSION: THE BAG SHOULD HAVE NOT BEEN LOADED AND I SHOULD HAVE BEEN MADE MORE AWARE OF THE SITUATION. STAYING CONNECTED WITH THE HEADSETS WOULD HAVE ALLEVIATED THE CONFUSION; BUT THE WILLINGNESS TO DEV FROM AND THE DISREGARD FOR BASIC SAFETY WAS THE MAIN ISSUE.