WebGl RAM requirements

I am trying to publish a build of my game as WebGL but I have run into a problem.
The RAM needed to run the game spikes at around 1.8 - 1.9GB in Chrome and 1.3 - 1.5GB in Firefox. After the initial loading is done, in Firefox the RAM usage goes down to about 800MB which is acceptable, but in chrome it stays at 1GB+.

According to the Editor Log the biggest assets in my project are the textures at around 100-150MB, and the rest is negligible. As far as scripts go, I am only using one FPS character and the lighting is Baked.
So what is causing the huge jump in RAM usage during loading? And is there any way to mitigate this?

The best way to find what’s causing that is using the profiler.

Here you have some instructions to profile a WebGL game: Unity - Manual: Profiler overview
Here’s some info on the Memory profiler: Unity - Manual: Memory Profiler module