Vol. 10, No.1 – Preface

Vol. 10, No. 1 (December 2005) – Preface

The OECD Health and Environmental Assessment of LAS

The Council on LAB/LAS Environmental Research (CLER) is pleased to provide in this issue of The CLER Review the SIDS1 Initial Assessment Report (SIAR) for linear alkylbenzene sulfonate (LAS), the world’s most widely used household detergent ingredient.

Just prior to this writing, the assessment was approved by the Organization for Economic Cooperation and Development (OECD), which represents the health and environmental regulatory authorities of the thirty most advanced industrialize nations.2 The assessment concludes that LAS “is low priority for further work” and thus of low regulatory concern.

Since LAS is the first cleaning product ingredient to complete the OECD assessment process, the conclusions of the SIDS assessment provide unequalled assurance to users of the health and environmental safety of LAS.

The assessment consists of an overview of the SIDS review process, a summary and conclusions document known as a SIDS Initial Assessment Profile, and the SIDS Initial Assessment Report (SIAR) document with three annexes. The first annex is an environmental and human exposure assessment for LAS and includes both environmental monitoring and exposure modeling data that is unprecedented in its scope. The second annex provides details of the assessment of the acute freshwater toxicity of commercial LAS, values that are critical to the international regulatory acceptance of any chemical. The final annex is an assessment of the chronic freshwater toxicity of commercial LAS, including calculation of a chronic threshold value protective of the freshwater environment. Calculation of such a value is only possible for substances such as LAS, for which a large and robust database is available.

The OECD acceptance of the LAS SIAR represents the culmination of nine years of collaborative efforts in researching, compiling and assessing the scientific information on the health and environmental properties of LAS. These efforts began in 1996 when CLER member companies volunteered to participate in the OECD SIDS assessment of LAS with the U.S. Environmental Protection Agency (EPA) representing the United States as the sponsor country. Interestingly, EPA proposed LAS as a candidate for assessment because of a request for information on LAS use in metal working fluids, an application that CLER has been unable to confirm. Nonetheless, because CLER had successful experience working with EPA in the OECD SIDS assessment of linear alkylbenzene (LAB) – completed in 1995 – CLER volunteered to lead an industry consortium to assess the health and environmental properties of LAS, including all major uses.

The Industry Coalition for the SIDS Assessment of LAS was formed in 1997 and consists of the five CLER members (Huntsman Corporation, Petresa International N.V., Quimica Venoco, Sasol North America and YPF SA) plus the following major LAS/LAB manufacturers or trade associations: Center for LAB Environmental and Technical Studies for Asia (CLETSA), Cognis Deutschland GmbH&Co.KG, Colgate-Palmolive Company, Kao Corporation, Lion Corporation, Stepan Company, TAYCA Corporation, The Dial Corporation, The Procter & Gamble Company and Unilever Household and Personal Care North America. Associate members of the consortium included: Mitsubishi Chemical Corporation, Nippon Petrochemicals Co., Ltd. and W.R. Grace & Company.

Assisted by technical experts from the member companies, the consortium began the enormous task of reviewing all of the available scientific information on LAS. This effort began with identifying all the available names and Chemical Abstract Service registry numbers for LAS (10 names in total are used in commerce in the US, Canada, Europe and Japan).

Next, the scientific literature was rigorously searched for published studies on the health and environmental properties of LAS and members were asked to provide any unpublished reports that also would be relevant. Altogether, over one thousand studies were retrieved and reviewed, and summaries of the key studies were prepared using an OECD prescribed format called a “robust study summary.” Studies were identified that fulfilled the required data set values for physical and chemical properties, biodegradation and removal in sewage treatment, aquatic toxicity and mammalian toxicology. In fact, the database for LAS is so extensive that it includes considerable data beyond the minimal SIDS requirements, including multiple studies for many of the required endpoints, and data on soil, sediment and saltwater environments that are beyond the required dataset.

At this same time, members of the consortium were surveyed to determine the current production volume and chemical composition of the LAS that they manufacture. This information proved to be important in demonstrating that the LAS produced in the U.S., Canada, Europe and Japan is quite consistent in its composition and thus all ten CAS numbers for LAS represented the same material.

Members of the consortium were also asked to provide information on the manufacturing processes for LAS. This proved useful in demonstrating to EPA and OECD that LAS was produced using safe manufacturing processes.

Finally, members of the consortium were asked to provide information on uses of LAS, including the levels of LAS in various categories of cleaning products. This information was combined with models of cleaning product use, developed by the Soap and Detergent Association, to estimate human exposure to LAS from cleaning product use.

Since the members of the consortium represent the vast majority of LAS production in the OECD member countries, OECD has high confidence that the data provided on LAS is representative of the entire industry. Indeed, several OECD members praised the consortium for its efforts in providing such a comprehensive assessment.

All of this data, compiled in the form of robust study summaries, are included in the data dossier that was provided to EPA for review and comment, and then provided to OECD. The OECD approved version of the LAS dossier, which is over 250 pages in length, is available in full on the CLER website (

The data in the dossier is then reviewed and assessed in the SIAR that is included in this volume of The CLER Review. Regarding health, the assessment demonstrates that maximal estimates of human exposures were considerably below toxicity thresholds for all cleaning product uses. For the environment, the assessment demonstrates that modern sewage treatment practices are highly effective in biodegrading and removing LAS from wastewater. Consequently, real world levels of LAS, if detected, are below toxicity thresholds for representative organisms in all parts of the environment that receive treated waste streams.

The completion of a favorable OECD SIDS assessment of LAS thus represents a significant milestone for CLER and the entire cleaning products industry. This would not have been possible without the willing collaboration and valuable technical contributions of all the companies and scientists involved, to whom our deepest appreciation is due and expressed.

John E. Heinze, Ph.D.

1. Screening Information Data Set, the OECD name for the minimum data requirements for evaluation of the properties of any chemical submitted for health and environmental assessment.

2. OECD member countries include: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Korea, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, Slovak Republic, Spain, Sweden, Switzerland, Turkey, United Kingdom, and the United States.