Rebuttal to "Flame retardants in UK furniture increase smoke toxicity more than they reduce fire growth rate" by S. McKenna, R. Birtles, K. Dickens, R. Walker, M. Spearpoint, A. Stec and R. Hull (2018 Apr;196:429-439. doi: 10.1016/j.chemosphere.2017.12.017. Epub 2017 Dec 5.)