There are many studies and achievements in producing chemicals to be used as flame retardants. However, those achievements came with side effects:

We may classify those compounds under 4 groups:

• Compositions made of phosphoric acid and hydrochloric acid. Those are compounds that release poisonous gases when burned. Thus their use is restricted.
• Nitrogenous compositions made of phenol and formaldeid when burned, release gases that consume the oxygen in the ambient. They are used in fire fighting, however consuming the oxygen and the poisonous gases result in endangering the life of the personnel or the living organisms in the area.
• Compositions made of trioxide and antimony aim to consume the oxygen by the release of ammonium oxide, however it is known that antimony trioxide contains %0, 15 arsenic and % 0, 05 lead thus are dangerous for human health.
• Compositions made by putting strong bases and acids into a reaction in order to consume the oxygen in the burning area however this reaction also results in poisonous gases.

• Some fire retardant wood coatings have been promoted in ways that encourage their misuse in structural applications. Model building codes do not permit fire retardant coatings to be used for structural applications.
• Coatings are only permitted for interior trim, paneling, cabinets and other non-structural uses. For all structural uses pressure impregnated FRTW[1] is required. When evaluating coatings, consider the following:
• Coatings may have been mistakenly accepted as FRTW by building officials, fire marshals, architects and contractors when they were are not aware of the differences between pressure impregnated fire retardant treatments and surface-applied fire retardant coatings. Pressure impregnated fire retardants, such as Fire-O, are permanent treatments and do not require additional reapplications.
• Third party quality control of the application process is required by model codes. FRTW is treated and redried in commercial pressure treating plants. An agency certification mark is applied to each piece indicating
• in-plant third party quality control, as required by the model codes.
• On the other hand, coatings are applied anywhere by on-site applicators. Unlike FRTW, which has in-plant third party quality control of the treating process, there is little or no third party quality control of the coating application at the jobsite.
• The UL Building Materials Directory states that for coatings the local building official is responsible for assuring proper application in the field. This is unnecessary with FRTW.
• Flame spread testing for FRTW is far more severe than for coatings. The basic test procedure in both cases is the familiar ASTM E-84 “Tunnel Test,” which is a 10-minute test. However, unlike coatings, FRTW must endure the test for an additional 20 minute duration. Codes require FRTW to have a flame spread rating of 25 or less (Class A) per ASTM E-84, plus there can be no significant progressive combustion when the test is extended to 30 minutes. The superficial protection provided by coatings cannot pass the 30-minute Tunnel Test. Unfortunately, since the test designation in both cases is “ASTM E-84,” it’s easy to mistake Class A 10-minute test results as meeting code requirements for structural use, which it does not.
• Codes require strength testing after high temperature/high humidity exposure. Coatings often claim little or no strength loss (there is little or no penetration into the wood) and their test data rarely includes high temperature exposure.
• For structural purposes, building codes require FRTW to be pressure applied and tested for flame spread under ASTM E-84, the extended version. Using a surface applied fire retardant coating is not allowed as an option.