Many people think Formaldehyde and Formalin are the same. They are wrong. Formalin is a form of a HydroCarbon molecule Formaldehyde. Formalin is a mixture of Formaldehyde and water. Most of the time it maintenance 37% water in the mixture. Formalin is an antiseptic, bactericide or fungicide.
Formalin is used in Textile Industry to make fabrics crease-resistant. It also used in the manufacture of automobiles and many others electrical and plastic compound. As I said earlier in the article; Formalin is an antiseptic and bactericide and fungicide, so Formalin's main uses as Disinfectant. It's used to stop producing bacteria. It also preserves and fixes tissue or cells.
It's complicated to say that Formalin is bad for health or not. Because it depends on how much has been used. In 1978, a research team of CIIT (Chemical Industry Institute of Toxicology) did a research about Formaldehyde on a few rats in 18 months long project. After 18 month interim reports, they found two different output. In total, 103 rats and 2 mice exposed to 14.3 ppm formaldehyde developed squamous cell carcinomas of the nose, as did two rats exposed to 5.6 ppm. As a result, They said using a low level of Formalin causes nothing. If someone using a high level of Formalin causes our diseases.
Source Fish; Where a chance of using Formalin.
Food and Agricultural Organization of the United Nation 'FAO's report about Formalin are using a low level of Formalin is Ok, but a high level of Formalin in food can be an indication of adulteration.
So, It seems a low level of Formalin causes us nothing, but a high level of Formalin may cost our lives. In Bangladesh, Most of the farmers (Producer) or sellers don't know what is the maximum range of using Formalin in food. They use Formalin on food with no idea about using level. For the mischief of them, we can suffer Cancer in future. So we need to beware about Formalin.