The coal fly ash is a very good concrete additive, too.
As to the relative cleanness of coal (compared to 40 years ago) it’s very clean today and as a NASA QA manager was fond of saying, “Those who insist on 100% safety don’t have the balls to live in the real world.”
Coal ash is used as a concrete additive because it’s not possible to do anything else with it. Even in concrete it will still gradually leach out heavy metals from the surface of the concrete itself as the material weathers out. Just like any other sedimentary rock weathering. Concrete is simply man made sedimentary rock that a lot of geologists kidding call urbanite when a freshman geologist student brings us a hand sample and is like look limestone conglomerate.
The point also is coal is never going to be zero emissions up the stacks of heavy metals where as natural gas and nuclear and every other form of power already is zero. There is no safe limits for heavy metals they were tolerated by.society because there was no other alternatives now there is and coal need to be in the history books.
Here is the actual EPA statement with the links to the actual limits here again thst are giving an advantage to coal all the others are not allowed to emit heavy metals at all. They only tell coal to cut by 67% that’s no where near zero.
Also coal gets a pass on it’s huge toxis forever waste piles and also it’s toxic run off. Both of which are real pollution and have nothing to do with CO2. Here again none of the other forms of energy have toxic run off nor toxic sludge ponds that a single accident here in the USA at a coal waste pond killed more people than all the nuclear accidents world wide. 40 people died in that pond breach. Only a handful died heroically at Chernobyl and one or two will also due to self sacrifice from Japan’s meltdown they are not dead yet but will be included in the numbers they stayed and got irradiated like hero’s they are.
Key point.
A final rule strengthening and updating the Mercury and Air Toxics Standards (MATS) for coal-fired power plants, tightening the emissions standard for toxic metals by 67 percent and finalizing a 70 percent reduction in the emissions standard for mercury from existing lignite-fired sources.
A final rule to reduce pollutants discharged through wastewater from coal-fired power plants by more than 660 million pounds per year, ensuring cleaner water for affected communities, including communities with environmental justice concerns that are disproportionately impacted.
A final rule that will require the safe management of coal ash that is placed in areas that were unregulated at the federal level until now, including at previously used disposal areas that may leak and contaminate groundwater.