Disposable e-cigarette disposed of in the masonry

It would also be questionable whether the construction contractor could simply deny that the e-cigarette was brought in by one of his workers... purely theoretically, anyone could gain access and dispose of their hazardous waste there

Of course, you go to the company and tell them what happened there.

And what is supposed to happen then? "Hello Mr. GU, the subcontractor mason or someone else disposed of their trash (e-cigarette butts) in the stones." Do you think the GU will say dududu or reprimand the company? You really have to come down harder with consequences. My opinion. But you're right: you do have to say something before you later have a disadvantage that you can no longer prove. You are basically standing somewhat alone in front of such a "trifle." I believe you can only achieve something by direct action. Visit the construction site during work, see who is smoking these vapes, and then make a loud scene in front of everyone during the breakfast break. You can prepare words and speeches. If necessary, come verbally with DNA and the police. Insulation, thermal bridges, economic damage, irresponsibility, and stupidity... However, this only works in theory for most people. But you can try, resolve to do it ;) Regarding the danger: I can't imagine that anything can still happen if it's airtight sealed. However, it is an environmental disgrace that can be annoying.

So cucumber slices and paper bags don't bother me. It stops with hazardous waste or liquid residues from construction chemicals.

The paper bag might partially contribute to a better U-value, but I'm not really keen on that :-D
Jokes aside.

Politely but firmly address your discovery with the contractor and ask him to support you in keeping the bricks in their factory condition, meaning no further fillers applied on site.

I've stopped counting how many buckets of trash I've disposed of myself by now. Just get used to it, that's that. Many companies hardly dare to reprimand their employees for fear they might take it personally and leave – at least that's my impression.

The plasterers have cleaned their hoses on previously uncontaminated ground, thrown leftovers of the 2K coating next to the light well, poured the remaining primer in front of the front door, wiped silicone, etc. on the bricks and of course much more. At some point, you just clean it up yourself. I can't hear the phrase "this is a construction site, not an operating room" anymore. If someone can't distinguish a construction site from a landfill, there's no helping them anyway.

Of course he can deny that. In an open shell construction, anyone can walk around. I still wonder to this day that during the severe building materials crisis at the end of 2021/beginning of 2022, nothing disappeared from our site.

Making a fuss... probably won't interest the workers much. At best, you get laughter; at worst, you get punched in the face.

And honestly. Where else are the cleaners supposed to clean their stuff? The painters will also clean their rollers in your sink... if they then drive an hour to the company with them, the tools are ruined.

Guys, this is a construction site, not a cleanroom.

Anyone who yells at the builders like a fury might as well order their construction from Wish.

How about the container that the plasterers had delivered specifically for their plaster surplus? That was maybe 20 or 30 liters of sludge at most, there would still have been space for it. But no, the Z0 floor probably looked so inviting. I had to transport that mess away today with a spade and wheelbarrow so that the landfill would even accept the rest from me.

When I once dumped a trowel full of hardened gypsum on the ground outdoors at a construction site 18 years ago, the architect immediately kicked me off the site. Today I know that was justified. When I work on a construction site, I also take care of my own waste at the end of the day or, within the scope of my work processes, consider how to handle the waste generated. So if that is already too much to ask, then I don’t know either. This general excuse about it being a construction site and nothing else is really worn out. Everywhere there is climate protection hysteria, but on the construction site all the filth is thrown and poured onto the meadow. The main thing is that the energy efficiency of the building is wonderful on paper; no one cares what happened before during the construction of this building.