More than 180 firefighters wearing protective suits were on Friday tackling a major blaze at a metal technology firm in Berlin's Lichterfelde area as authorities warned of toxic smoke, Paralel.Az reports citing The Local Germany.

The blaze broke out in the first floor of metal technology factory ‘Diehl Metal Applications’ on the Stichkanal in Lichterfelde, south-west Berlin around 10:30 am.

On Friday afternoon, a fire brigade spokesperson said an area of over 2,000 square metres was on fire in the four-storey building.

As of 5 pm, the fire was reportedly still not under control.

According to the spokesman, the fire had spread to the roof, with parts of the building collapsing.

As the company also stores and processes chemicals in various quantities, there are concerns over harmful fumes in the smoke.

"We can confirm that chemicals are also burning in the building," said the fire service. "Sulphuric acid and copper cyanide were stored there. There is a risk of hydrogen cyanide forming and rising into the air with the smoke."

Hydrogen cyanide is a highly toxic substance.

The Berlin state government said that residents "in the affected areas of the toxic fumes caused by the fire" were warned through the NINA warning app at midday.

According to a fire and rescue spokesperson, no injuries have been reported.

The cause of the fire has not yet been established.

Some early reports suggested that the Diehl Metal location might also store defence products. According to a report by the New Voice of Ukraine, Diehl Defence, which manufactures weapons to be used in Ukraine, operates out of southern Germany and would not be affected by this fire.