I am considering to buy a commercial realestate that is 70 years old
and has asbestos in the building.  Would someone educate me if there
is any company offering insurance to tenants/employees exposed to
asbestos?

Of course, I intend to hire a firm to monitor asbestos level in the
air and periodic inspections to make sure that I abide by the lawful
protection necessary.

FYI-- asbestos is not harmful just existing in a building. It is when
measures are taken to remove the asbestos that it becomes harmful--
when it's removed all the particles are released into the air and
subsequently into lungs. Many good-intentioned people have removed
asbestos from a building, thus putting everyone in danger. But if it
is just left there, it's fine.

Keystroke, just try explaining that to a pack of ravening lawyers
promising huge payouts to your former and current tenants.

You are both right, but first someone has to start a case based on
asbestositis (?):
1) which is extremely unlikely;
2) the decease has to be proven, which it can be;
3) since the decease seldom becomes evident until pretty far advanced,
the chance of it developing to that stage in an undisturbed home
environment is very unlikely.

In Germany, millions  - maybe nationwide, billions -  have been spent
to remove asbestos from schools:  big scare, parents and politicians
all agog.  But the kids spend a maximum 8 years in a school, 13 years
in two or three schools, and of course there have never been any
cases, nor among the teachers who spend 20-30 years in the schools,
nor among superintendents and their families who lived in the
buildings.

I am on Keystroke's side.  
Myo

I am digging into my raddled memory, but my understanding is that a UK
company cannot be shut down while there are still outstanding cases
against it.

Hence one dead behemoth is still kept alive.

Most serious underwriting ultimately goes through Lloyds of London,
and from memory they took a beating from asbestosis.

Also from memory, there are different types of asbestos, I vaguely
recall that 'blue' was the really lethal one.

From what a developer friend of mine told me, I would be strongly
inclined to clear the building (assuming you can) and clear out
anything suspicious.

Blue and Brown asbestos are the most dangerous,  white asbestos is
relatively harmless
Lloyds are NOT taking on any new asbestos insurance or re-insurance

@Kemlo, I have a vague memory that Lloyds wrapped up all existing
cover in some sort of ring fenced fund.

Interesting that white asbestos is relatively harmless, I have happy
memories from 35 years ago, of sitting on a farm buiding's roof sawing
up sheets of asbestos.

@tinypatient-ga 
From talking to UK developers, I would bite the bullet and get any
asbestos removed by a 'specialist' company. It may be harmless, but it
is a legal sword of Damocles.
I believe Kemlo is quite correct, getting insurance would be very
difficult, I would be very suspicious of anyone offering cover.