This study evaluated fire retardant (FR) versus non-FR sofas and found that FR treated foam does not appear to increase the chronic or acute toxicity of the smoke in a fire compared to non-FR treated foam.
Notably, the results suggested that flexible polyurethane foams (both flame retardant and non-flame retardant) smoke toxicity is less than or equal to that created by wood on a mass/mass basis; and wood contributes a significantly greater mass percentage to residential fires and is therefore a much greater contributor to residential fire smoke toxicity.1 Source: Blais, Matthew, and Karen Carpenter. “Flexible polyurethane foams: a comparative measurement of toxic vapors and other toxic emissions in controlled combustion environments of foams with and without fire retardants.” Fire Technology 51.1 (2015): 3-18.