Sct departure controller reported a departing aircraft was in immediate conflict and received a TCAS...

Narrative:

I was working a radar departure sector and acknowledged aircraft X in the departure rundown list. At the time; there wasn't a VFR conflict in the departure corridor. A little bit of time passed; and there were 2 VFR aircraft in the corridor so I called tower to tell them not to launch aircraft X. As I was calling; I saw the splat (aircraft X's target) and knew it was too late. One target was at 1;900 feet; the other was at 2;800 feet. I could not stop aircraft X at any safe altitude. I asked tower if they see the traffic and they said something to the effect of they had it or that they would take care of it. As I watched the situation I called tower again to tell them to keep aircraft X climbing. They said they were not talking to him. Aircraft X and one of the targets were almost right on top of each other at the same altitude. Aircraft X was checking in as I was on the line with tower telling them to keep him climbing. Aircraft X checked in out of 3;300 feet responding to an RA.[suggest] make lgb airspace a class C before there is a fatality.

Original NASA ASRS Text

Title: SCT Departure Controller reported a departing aircraft was in immediate conflict and received a TCAS RA with VFR aircraft transitioning the airspace not in communication with ATC.

Narrative: I was working a Radar Departure sector and acknowledged Aircraft X in the departure rundown list. At the time; there wasn't a VFR conflict in the departure corridor. A little bit of time passed; and there were 2 VFR aircraft in the corridor so I called Tower to tell them not to launch Aircraft X. As I was calling; I saw the splat (Aircraft X's target) and knew it was too late. One target was at 1;900 feet; the other was at 2;800 feet. I could not stop Aircraft X at any safe altitude. I asked Tower if they see the traffic and they said something to the effect of they had it or that they would take care of it. As I watched the situation I called Tower again to tell them to keep Aircraft X climbing. They said they were not talking to him. Aircraft X and one of the targets were almost right on top of each other at the same altitude. Aircraft X was checking in as I was on the line with Tower telling them to keep him climbing. Aircraft X checked in out of 3;300 feet responding to an RA.[Suggest] make LGB airspace a Class C before there is a fatality.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1468526
Time
Date	201707
Local Time Of Day	1801-2400
Place
Locale Reference	SCT.TRACON
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Function	Departure
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 4.0
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict

Sct departure controller reported a departing aircraft was in immediate conflict and received a TCAS RA with VFR aircraft transitioning the airspace not in communication with ATC.