carbon monoxide

Dorset Police, who previously said carbon monoxide poisoning was a possible cause, said the deaths were still being treated as "unexplained".

Cigarettes release thousands of different chemicals when they burn, including carbon monoxide, lead and ammonia.

In the case of large, multiple-battery fires, they can burn for days, all the while releasing toxic gases such as hydrogen fluoride, hydrogen chloride, carbon monoxide and carbon dioxide.

The employees were treated for heat-related illness, the report said, but when their symptoms didn’t improve, they were treated at a hospital for carbon monoxide exposure.

Investigation work is continuing after three people died from suspected carbon monoxide poisoning at a care home.