What is the difference between the "no reasonable possibility" standard and the "harmless beyond a reasonable doubt" standard?

My colleagues dispute my analysis on the ground that the cases I rely upon "have mistakenly adopted a test for prejudice which was devised for [23 Cal.App.4th 1690] capital cases, and which is equivalent to the 'harmless beyond a reasonable doubt' standard applicable to deprivations of federal constitutional rights." (Maj. opn., at p. 370, citing Chapman v. California (1967) 386 U.S. 18, 87 S.Ct. 824, 17 L.Ed.2d 705.) The majority's distinction is both irrelevant and inaccurate. First, contrary to the majority's assertion, the "no reasonable possibility" standard depends neither on the holdings in capital cases nor on the federal Chapman standard, but on a common sense recognition that it is subversive of justice and substantive policy to sanction a class of error which, by its nature, insulates itself from appellate review.