Hi All! Can anyone tell me what is this white stuff all over my mulch? The mulch is Preen brand black mulch and it was purchased about 2 months ago but I just got around to laying it down recently. Is it mold from sitting in the bags for a couple months in the heat and humidity? I am pregnant and wore a mask and gloves while laying it down but I'm nervous that I've exposed myself to something really dangerous. Any advice would be appreciated as to what this is. Thank you!