Factors determining the permeation of eight alkylbenzene isomers of molecular weight 120.19 (three ethyl toluenes, three trimethylbenzenes, and two propyl benzenes) were investigated for a lined nitrile industrial type glove using an ASTM-type cell, liquid collection, and gas chromatography/mass spectrometry. The initial permeation rate P-i correlated inversely with the logarithm of the lag time t(l). The logarithm of the steady-state permeation rate P-s correlated inversely with the logarithm of the breakthrough time t(b) P-s/P-i for a given compound correlated directly with P-s and with t(l)/t(b) P-i depended directly on the logarithm of the entropy of fusion divided by the square of the refractive index and divided by the solubility parameter. The t(b) was inversely correlated to the logarithm of the water solubility. The logarithm of t(l) was most directly correlated to the entropy of vaporization. High P-s for 1,2,4-trimethylbenzene, m-ethyltoluene, and p-ethyl toluene was linked to a common structural similarity to 1,2,4-trimethylbenzene relative to the unhindered geometry of the methyl group in the ethyl side chain. The existence of optimum radii of gyration for enhanced P-s and for long t(b) suggested that the protective properties of nitrile followed discontinuous relationships rather than continuous ones and so are not explainable by correlative relationships of continuous functions.