Preventing Percutaneous Absorption of Industrial Chemicals: The “Skin” Denotation

Abstract

Percutaneous absorption has received comparatively little attention in occupational health, although this route of entry has repeatedly caused occupation-related intoxications. In practice, the evaluation of skin penetration rates is far from simple. Much evidence has been obtained from studies of chemicals used for cosmetics and topical therapeutics, but the information available on compounds encountered in occupational health is limited. The data obtained from experimental studies have confirmed that the concentration, type of vehicle, skin area, skin condition, and extent of occlusion are important factors in determining the degree of percutaneous absorption, but no general model has been developed. Also, too little is known about the basic chemical properties governing the rate of penetration. Thus, prediction is difficult and bound to be rather inaccurate. Current preventive practice follows the procedure used by ACGIH and is mainly based on a "skin" denotation in official listings of chemicals to which exposure limits have been allocated. The number of substances and groups of chemicals which have received skin denotation in 17 selected countries varies between 24 and 179 and a total of 275 are listed as a skin hazard in one or more countries; ACGIH lists 143. Thus, the denotation practice varies. As an unfortunate result of these discrepancies and the dichotomy of skin denotation, the absence of skin denotation may erroneously indicate that efforts to protect the skin are unnecessary. Thus, an evaluation of skin penetration potentials should be incorporated in occupational health practice as a supplement to the official denotations.

Proposal for the assessment of quantitative dermal exposure limits in occupational environments: Part 1. Development of a concept to derive a quantitative dermal occupational exposure limit.

“…Besides, the absence of a skin notation does not imply that risk due to skin exposure can be ignored. 7 The scientific basis underlying the skin notation in the TLV list of the ACGIH is not always well documented. 8 In The Netherlands, a skin notation is applied by the Dutch Expert Committee on Occupational Standards (DECOS) predominantly based on a strategy proposed by European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC).…”

Skin absorption in vitro of glycol ethers

“…If we use acetone as a vehicle, an enhancing eect is documented for some solvents tested, with dierent increases: higher for EGMEE (Larese et al 1994) and for EGDME, lower for PGMMEac. The fact is that it is dicult to predict the skin penetration of any given solvent mixture (Grandjean et al 1988), and this is a great problem, especially in an industrial setting where workers are principally exposed to mixtures rather than to pure substances. However, some hypotheses can be made: a solvent mixture, particularly in the presence of acetone, modi®es permeation of GEs, but in most cases no signi®cant increase in absorption was found.…”

A Critique of Assumptions About Selecting Chemical-Resistant Gloves: A Case for Workplace Evaluation of Glove Efficacy

“…(3) By comparison, a European Economic Commission-sponsored survey in 1990 identi ed 275 chemicals listed by various countries as skin absorption hazards. (4) In the United States the number of compounds with the potential to cause skin damage or systemic toxicity and used in the workplace may far exceed the number indicated by skin notations. This is illustrated by an evaluation of 132 chemicals with a TLV; 92 percent were calculated to be capable of signi cant dermal absorption and toxicity based on their skin permeation potential, but only 35 percent of the 132 chemicals carried a skin notation.…”