From the Guidelines

Heating food in a microwave oven is not harmful.

Microwaving food does not increase cancer risk, as microwaves are a form of nonionizing electromagnetic radiation 1.
High-temperature cooking methods, such as grilling, smoking, or pan-frying, can cause chemical reactions that form carcinogenic heterocyclic amines, but microwaving minimizes the production of these chemicals 1.
Techniques like braising, steaming, poaching, stewing, and microwaving meats are recommended as they minimize the production of potentially carcinogenic chemicals 1.
The use of microwave-safe containers is important, as some containers can release harmful substances like phthalates or bisphenol A during microwaving 1.
It is essential to follow proper food handling and storage guidelines to minimize the risk of contamination and exposure to harmful substances 1.

The American Cancer Society guidelines emphasize the importance of adequate cooking to kill harmful microorganisms in meat, but also suggest that high-temperature cooking methods may increase cancer risk 1.
The evidence suggests that microwaving is a safe cooking method, but it is crucial to use microwave-safe containers and follow proper cooking guidelines to minimize the risk of contamination and exposure to harmful substances 1.

From the Research

Microwave ovens can cause heating when polar materials absorb microwaves, but they do not confer any special qualities on the food 2.
The lethal effects of microwaves on microorganisms and trichinae are due to heat, and the speed and evenness of heating are influenced by the composition and mass of the food as well as the features of the appliance 2.
Microwave heating is more "food dependent" than conventional heating, and the manufacturer-recommended microwave treatment time for some foods may not destroy high levels of bacteria 3.

Nutrient content and retention of microwave-cooked or reheated foods are equal to or better than the same product prepared conventionally or held hot in a foodservice operation 4.
Microwave heating at a high power level can cause greater acrylamide formation in products than conventional food heat treatment, which may be due to differences in its formation during microwave heating and conventional methods 5.
Short exposure to microwaves at low power may even limit the formation of acrylamide during the final heat treatment 5.

Microwave heating is a fast-drying method that utilizes electrical energy to generate heat energy, and it can be used for food preservation 6.
The temperature variations and drying characteristics of food samples can be monitored, and the microwave oven can achieve maximum drying efficiency with a slab-shaped sample 6.
Economic analysis of microwave ovens has been done, and the payback period has been found to be around 3.27 years 6.

Safety to the users of microwave ovens is assured by strict government regulations 2.
A domestic microwave oven is not harmful, but a commercial-level oven may be slightly harmful when operated at high frequency 6.