As mentioned earlier, it is fire and heat-resistant. Thus, if you have been using it in microwaves, you won't find it catching fire or getting charred. However, it tends to absorb the radiation and heat. This makes one wonder if it is really suitable to use as cookware. Well, the answer is NO! This is because it tends to absorb the radiation and starts to decompose, which makes it highly dangerous.
If it absorbs enough heat, it will become unstable and release bubbles as it breaks down in structure. It contains nitrogen that does not allow it to burn. Thus, it just breaks down to its original elements urea and cyromazine. These two compounds are extremely dangerous and highly toxic.
Experts have found melamine to be harmful when inhaled, swallowed, or absorbed through the skin. The US Food and Drug Administration (FDA) has found that when melamine and cyanuric acid enters the bloodstream it forms crystals that can block the renal tubes, leading to kidney damage or even failure. Thus, heating it in a microwave oven is a big no no!
Is Melamine Dinnerware Microwave Safe ?