USP Grade Methylene Blue Powder - 5 gm

The methylene blue ships in 5 x 1 gram containers with a screw top and stored inside a sealed bag which has a rip off top.I had purchased distilled water and placed the container to mix the methylene blue inside a large stainless steel pan, in case of any spillage. Only after ripping the top off the bag and starting to extract the first of the small containers did I notice that the screw lid on that container had worked loose and some of the fine blue powder inside had spilled out.By that time it was too late. Only a small amount puffed out off the bag and tiny specks landed on my hands and nearby surfaces but that was enough to require well over 80 minutes of cleaning my hands, the surfaces it landed on, and then trying to clean it off the container itself and the other containers.If the ability of tiny specks of dust to turn huge volumes of water blue is an indication of authenticty then this is genuine methylene blue. However, the very fact that miniscule amounts of this substance can stain almost anything blue should mean that these containers are verified to be very tightly closed before shipping, perhaps even with a seal around the top to prevent the top working loose.I was lucky that the pan was sitting on a large silicone mat but I still had to clean everything down then rinse everything repeatedly as I could not leave any methylene blue on any surface. This stuff takes a huge amount of water to dilute the colour. It stained my resin sink plus the white work surface some dripped onto and they took absolutely ages to clean. I had to use bleach, soap and 4 magic sponges, which are now all blue and in the bin.If I purchase this methylene blue powder again I will first closely check the sealed bag with the 5 small containers and if there is any sign of leakage it will be getting sent staright back to Amazon.!