Hydrogen is not toxic. Hydrogen is an industrial reagent. However, hydrogen has special properties. If the hydrogen content in the air is high, it will cause hypoxia in the air, which is harmful to the human body. Furthermore, it is explosive and there is no flame when burning, which is a an extremely dangerous gas.
If a large amount of hydrogen is inhaled, because the hydrogen is relatively light, it will spread around, the alveoli will swell, and the entire lung will compress the heart like edema, making it difficult to exhale and breathe, which is very dangerous.
But at room temperature, hydrogen is relatively inactive, but can be activated with a suitable catalyst. At high temperatures, hydrogen is very reactive. With the exception of noble gas elements, almost all elements can form compounds with hydrogen. The hydrides of non-metal elements are usually called hydrogen halide, hydrogen sulfide, etc.; the hydrides of metal elements are called metal hydrides, such as lithium hydride, calcium hydride, etc.
In addition, hydrogen is not only an important industrial raw material, but also the energy of the future and the cleanest fuel.