It is not actually. The mercury content is very hazardous in large amounts. The problem is,as with so many things, a questions of scale. The odd tube here and there discarded into landfill is not in itself likely to be a hazard. Scale that up the millions of tubes discarded each year and it amounts to significant amount of a very toxic material that does not decompose.
Like everything with the green issue, the whole thing is scewed up. Scale up the millions of tubes discarded every amounts to significant amounts of toxic material has to considered in the context of the thousands of gallons of petrol that will now be burnt by householders taking their old tubes and compact bulbs to the fuse tip. I probabley dispose of one, possibley two tubes a year. I think that I have only had to replace one compact bulb over a period of ten years. Considering the amount of hazardous waste that would generate as a percentage of just the tons of useless packaging I get through in a year verses the trips to the tip that I am now expected to make doesn't make sense. But it is like the criticism levelled this week on the amount of water used by households. With 30% of water lost before it even reaches the tap the environmentalists are levelling their anger at the wrong people.
This is a common market thing hyped up by the tube disposal "industry".
I've seen an advert that just one fluorescent tube contains enough mercury to contaminate 30,000 Cubic Metres of groundwater. What the ad avoided saying is that it the Mercury doesn't actually end up in groundwater most of it gets sequestered by chemicals (Sulphur ?) in the environment.
Not far from where I live there's a quite substantial amount of water emerging from a bleb in the middle of a road - obviously a broken water main - where it runs down the hill and down a drain; the road is always wet. Last week I decided to report it to United Utilities - I couldn't believe that somebody hadn't already done so as it had been going for ages, but anyway... (In my defence, had it been in my road I'd have phoned UU straight away, but as there must several hundred homes between me and the leak, I didn't think it was really down to me!).
So, I got through on the phone, and the nice lady said, "Ah yes, we already know about that leak, thanks. Somebody reported it in.... er, August".
In cool conditions it condenses to liquid Mercury. When the tube is running the Mercury vapourises. It is this that is responsible for the warm up delay that cheap compact fluorescents exhibit.
No it's the actual metal of the filaments which gets ripped off the filament surface by the discharge, especially if the filaments aren't hot enough, at start-up for instance, or if the ballast &/or starter doesn't provide enough pre-heat. Eventually this leaves the filaments thin and weak and they break.
Probably the origin of stories that it's cheaper to leave fluorescents on than switch them off.
I hesitate to jump to their defence, but it can be quite difficult to get permission to close a road for roadworks. Lots of rules about how many times a year and how many different services club together to share the inconvenience, etc. Having said that, they don't really seem to care a great deal if it's a cost to them to do something (you can bet your life if a customer was benefiting from something they'd jump to it!).
In modern tubes, it's tiny though. I saw a discussion of this relating to the World Trade Center collapse. Some of those nearby were concerned they might have got mercury poisoning from the tubes in the building breaking. They might have a small valid concern about mercury poison, but not from the tubes. The mercury released from the teeth fillings of the people who died is orders of magnitude higher. In the UK, it averages 3g per person at the crematorium.
Actually, it's the emission coating on the filaments, not the metal. Once the emission coating is all sputtered off, the filaments can't transfer enough current into the gas to maintain the discharge, unless the control gear has enough voltage headroom to make the tube operate as a cold cathode tube.
This will happen if the tube continues running in cold cathode mode after the emission coating is all gone. This is dangerous as it will overheat the tube ends, with the possibility of melting the lampholder, igniting something nearby, or causing the glass to crack or melt and the tube falling out. Control gear should ensure a tube which has lost it's emission coating (and is strictly dead) is not allowed to continue operating at higher tube voltages until catastophic failure, although I've certainly got some examples which don't.
Some years ago the dentist showed me a container where he collected left over amalgam filling material recovered from utensils and a filter under the drain of the little spitoon.
It wasn't a large box but weighed several kilos.
I gradually had old childhood fillings replaced until they were all gone. I would have liked to have lost more weight but every little helps.
You must be spending your pension on private dentistry. Apart from front teeth you only get amalgam fillings (but I haven't had any for about 5 years).
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.