Black Mastic under tiles - dangerous?

[RPB123]

I have had some tiles removed from a floor and underneath is a black mastic.

The property is mid-60's so I am suspecting that the mastic may contain asbestos.

Is it safe to walk over the mastic or will this potentially release asbestos fibres?

Same question in respect of sweeping the floor.

 

[Nige F]

A thin layer of mastic that you can see the screed through in parts ? Or a solid asphalt floor ? either way the only place asbestos could be is bound into the tiles - Marley tiles of that age had some but if you check on t'net you'll find they're low risk . The mastic won't have any - fibres are only released if a sheet of the stuff is cut/broken off etc.

 

[Deleted member 174758]

Old Marley (and similar. e.g Accoflex, Kenflex, etc) tiles often contain chrysotile (white asbestos) and may well have been fixed down using asphaltic cutback adhesive, an older type of mastic made with asphalt-based cement. Some cutback adhesives contained asbestos (source: UKATA), so it isn't completely correct to say that the adhesive is asbestos-free as in some cases it isn't. The only way to be certain is to get a test done

 

[Tigercubrider]

I suspect that there was more asbestos in the tiles that you removed than in the bitumen that held them down