I understand creosote, I used it in railroad ties (retaining walls), on underpinning under homes, piers on wharfs, and the best paint we could buy for exterior wood siding was creosote based, the painters had to be careful not to allow it to splatter into their eyes, and wear long sleve shirts so that it wouldn't "sting" their skin.
I don't understand Rockwool, the article doesn't say but was Rockwool Industries using/making creosote products at their location or is there something toxic in rockwool? Rockwool insulation is still used today as a more expensive, supposedly better insulation, Greenies love rockwool insulation over fiberglass because it's more dense slowing air infiltration, it's available in both batts and boards, on one house recently I asked for an alternative bid on rockwool and it was double, back in the 50s it was the same price as fiberglass, I asked the estimater why and he explained that they purchass fiberglass in such bulk that they get better pricing, few people will pay the additional money for rockwool.
