A coating colloquially known as popcorn, due to its popcorn appearance, which contained the mineral raw material vermiculite mixed with gypsum plaster. Exfoliated vermiculite ore has natural fire retardant qualities and is still used industrially. Asbestos was not intentionally included in the spray-on coating.

Vermiculite can be naturally contaminated with asbestos, coexisting in the sub-strata at its mined source. This was the case for a mine in Libby, Montana USA, which supplied a large amount globally in the 20th Century.

Just like the asbestos coatings, it was applied with industrial-sized sprayers as insulation on the underside of roofs and in multi-storey ceiling tween-spaces on underside of floors. Used to achieve building fire-rating on steel and reinforced concrete beams/columns. 

Occasionally sprayed externally as a façade, such as in front porch areas.  Sprayed onto internal residential ceilings.

While these older coatings are a risk, not all vermiculite is contaminated and should be tested to confirm the presence of asbestos.