LINEAR ALKYL BENZENE SULPHONIC ACID Linear Alkyl Benzene Sulphonic Acid Chemical Name: Linear Alkyl Benzene Sulphonic Acid; Linear Alkyl Benzene Sulphonic Acid Description and Uses: Linear Alkyl Benzene Sulphonic Acid; is an anionic surfactant commonly used in the manufacture of detergents and emulsifiers. It is environmentally friendly as it can be dried as powder. Usage areas LABSA is formed by the reaction of Linear Alkyl Benzene Sulphonic Acid (LAB) with SO3 (sulfonation). Today, LABSA is used as the main surfactant in liquid, gel or powder detergent production processes. It is one of the main raw materials of synthetic detergent industry. Laundry, dishwasher powder detergents, detergent gels, liquid soaps, cleaning powders, oily soaps and so on. as. It is used as mercerizing and washing agent in textile sector. As the raw material of detergent, it is used in the production of alkynbenzene solphonic acid sodium in decontamination, emulsion, dispersion performance, wetting and foam properties. It is widely used in various detergent and emulsion production such as washing powder, dishwashing detergent, light or hard dirt detergent, textile industry cleaner, paint assistant, coating and leather making industry and paper making industry. PRODUCT IDENTIFICATION CAS NO. 27176-87-0 LINEAR ALKYL BENZENE SULPHONIC ACID EINECS NO. 248-289-4 FORMULA CH3(CH2)11C6H4SO3H SYNONYMS Dodecylbenzene Sulfonic Acid (Strait Chain); LAS; LABSA; Laurylbenzenesulfonic Acid; Laurylbenzenesulfonate; n-Dodecylbenzene Sulfonic Acid; Alkylbenzene sulphonate, sodium salt; Linear Alkyl benzene Sulphonic Acid; Dodecylbenzolsulfonsäure (German); ácido dodecilbenceno sulfónico (Spanish); Acide dodécylbenzènesulfonique (French); CLASSIFICATION Anionic Surfactant DESCRIPTION OF LABSA Linear alkyl benzene sulphonic acid is the largest-volume synthetic surfactant because of its relatively low cost, good performance, the fact that it can be dried to a stable powder and the biodegradable environmental friendliness as it has straight chain. LABSA is an anionic surfactants with molecules characterized by a hydrophobic and a hydrophilic group. Alpha-olefin sulfonates (AOS) alkyl sulfates (AS) are also examples of commercial anionic surfactants. They are nonvolatile compounds produced by sulfonation. LABSA are complex mixtures of homologues of different alkyl chain lengths (C10 to C13 or C14) and phenyl positional isomers of 2 to 5-phenyl in proportions dictated by the starting materials and reaction conditions, each containing an aromatic ring sulfonated at the para position and attached to a linear alkyl chain at any position with the exception of terminal one (1-phenyl). The properties of LABSA differ in physical and chemical properties according to the alkyl chain length, resulting in formulations for various applications. The starting material LABSA (linear alkylbenzene) is produced by the alkylation of benzene with n-paraffins in the presence of hydrogen fluoride (HF) or aluminium chloride (AlCl3) as a catalyst. LABSA is produced by the sulfonation of LAB with oleum in batch reactors. Other sulfonation alternative reagents are sulfuric acid, diluted sulfur trioxide, chlorosulfonic acid and sulfamic acid on falling film reactors. LABSA are then neutralized to the desired salt (sodium, ammonium, calcium, potassium, and triethanolamine salts). Surfactants are widely used in the industry needed to improve contact between polar and non-polar media such as between oil and water or between water and minerals. Linear alkyl benzene sulphonic acid is mainly used to produce household detergents including laundry powders, laundry liquids, dishwashing liquids and other household cleaners as well as in numerous industrial applications like as a coupling agent and as an emulsifier for agricultural herbicides and in emulsion polymerization. PHYSICAL AND CHEMICAL PROPERTIES Household detergents including laundry powders, laundry liquids, dishwashing liquids and other household cleaners. Industrial applications of wetting agent, emulsifier for agricultural herbicides and in polymerization. LABSA HOMOLOGUES AND SALTS Linear Alkyl benzene sulphonic acid 27176-87-0 25155-30-0 (Sodium) Tridecylbenzene sulfonic acid 25496-01-9 26248-24-8 (Sodium) Tetradecylbenzene sulfonic acid 30776-59-1 28348-61-0 (Sodium) Pentadecylbenzene sulfonic acid 61215-89-2 64716-02-5 (Potassium) Hexadecylbenzene sulfonic acid 16722-32-0 64716-00-3 (Potassium) Heptadecylbenzene sulfonic acid 39735-13-2 Linear Alkyl benzene Sulphonic Acid (LABSA)/Linear Alkylate Sulfonate (LAS) Linear alkyl benzene sulphonic acid (LABSA) is prepared commercially by sulfonating linear alkylbenzene (LAB). Linear alkylbenzene sulfonate (LABSA), the world’s largest-volume synthetic surfactant, which includes the various salts of sulfonated alkylbenzenes, is widely used in household detergents as well as in numerous industrial applications. The LABSA market is driven by the markets for LABSA, primarily household detergents. Linear alkylbenzene sulfonate was developed as a biodegradable replacement for nonlinear (branched) alkylbenzene sulfonate (BAS) and has largely replaced BAS in household detergents throughout the world. The pattern of LABSA consumption demonstrates the overwhelming preference by consumers for liquid laundry detergents in North America, whereas powders continue to be the dominant products in Western Europe, Japan, and China. Comparable and reliable data in other world regions are generally unavailable. In these less-developed world areas, LABSA is essentially used only in laundry powders (particularly in India and Indonesia) and hand dishwashing liquids. The latter are often used as general-purpose cleaners. The following pie chart shows world consumption of LABSA: About 82–87% of LABSA is used in household detergents, including laundry powders, laundry liquids, dishwashing liquids, and other household cleaners. Industrial, institutional, and commercial cleaners account for most of the other applications, but LABSA is also used as an emulsifier (e.g., for agricultural herbicides and in emulsion polymerization) and as a wetting agent. Very small volumes are also used in personal care applications. Demand in the North American household segment fell sharply in 2000–11, as a result of several developments, including reformulations away from LABSA to alternative surfactants because of cost considerations, the greater use of enzymes, and adverse economic conditions that resulted in lower overall surfactant levels in detergents. However, consumption stabilized during 2011–17. Although consumption of LABSA will likely stabilize or decline slightly in the highly developed regions, it will increase by 3.0–5.0% in some less-developed regions or countries, such as the Middle East, Africa, India, and China, as well as Southeast Asia. As a result of the rapid growth of LABSA demand in the Asia Pacific region, demand in the region accounted for over half of global demand in 2017. The worldwide growth of LABSA will be negatively impacted by the efforts of detergent manufacturers to reduce the active content in their surfactant formulations, by the shift to liquid detergents in some countries (which benefits competing surfactants), and by less consumer overdosing (particularly in North America with unit dose laundry products, assuming they continue to take some market share from traditional liquid detergents). However, consumption of LABSA will be positively affected in countries/regions such as India, China, Africa, and the Middle East, where powder detergents are still a very large part of the laundry detergent market. Linear alkylbenzene sulfonate competes with several other major surfactants for use in household detergents. Some of the competitive surfactants have greater hard-water tolerance and better compatibility with enzymes and are milder than LABSA. Historically, however, LABSA has most often been lower in cost and has had other more favorable properties compared with competing surfactants. During 2002–06, very high crude oil prices made LABSA far less competitive than had been true in most years since its introduction. During 2007–11, LABSA prices tracked more closely those of the competitive surfactants. This led to a more stable pattern of consumption, even as prices for all surfactants continued to be very volatile. From late 2014 through 2017, low crude oil prices helped LABSA become more competitive. LABSA/LAS production is impacted by the supply situation for competing products—mainly alcohol ether sulfates (AES). Shortages in AES supply or its high price has usually favored the use of LABSA/LAS. In the developing world, LABSA competes with soaps. Alkylbenzene sulfonates are a class of anionic surfactants, consisting of a hydrophilic sulfonate head-group and a hydrophobic alkylbenzene tail-group. Along with sodium laureth sulfate they are one of the oldest and most widely used synthetic detergents and may be found in numerous personal-care products (soaps, shampoos, toothpaste etc.) and household-care products (laundry detergent, dishwashing liquid, spray cleaner etc.).[1] They were first introduced in the 1930s in the form of branched alkylbenzene sulfonates (BAS) however following environmental concerns these were replaced with linear alkylbenzene sulfonates (LABSA) during the 1960s.[2] Since then production has increased significantly from about 1 million tons in 1980, to around 3.5 million tons in 2016, making them most produced anionic surfactant after soaps. Contents 1 Branched alkylbenzene sulfonates 2 Linear alkyl benzene Sulphonic Acid sulfonates 3 Structure property relationships 4 Environmental fate 5 References Branched alkylbenzene sulfonates An example of a branched alkylbenzene sulfonate (BAS) Branched alkylbenzene sulfonates (BAS) were first introduced in the early 1930s and saw significant growth from the late 1940s onwards,[3] in early literature these synthetic detergents are often abbreviated as syndets. They were prepared by the Friedel–Crafts alkylation of benzene with 'propylene tetramer' (also called tetrapropylene) followed by sulfonation. Propylene tetramer being a broad term for a mixture of compounds formed by the oligomerization of propene, its use gave a mixture of highly branched structures.[4] Compared to traditional soaps BAS offered superior tolerance to hard water and better foaming.[5] However, the highly branched tail made it difficult to biodegrade.[6] BAS was widely blamed for the formation of large expanses of stable foam in areas of wastewater discharge such as lakes, rivers and coastal areas (sea foams), as well as foaming problems encountered in sewage treatment[7] and contamination of drinking water.[8] As such BAS was phased out of most detergent products during the 1960s, being replaced with linear alkylbenzene sulfonates (LABSA). It is still important in certain agrochemical and industrial applications, where rapid biodegradability is of reduced importance. Linear alkylbenzene sulfonates An example of a linear alkylbenzene sulfonate (LAS) Linear alkylbenzene sulfonates (LAS) are prepared industrially by the sulfonation of linear alkylbenzenes (LABSA), which can themselves be prepared in several ways.[2] In the most common route benzene is alkylated by long chain monoalkenes (e.g. dodecene) using hydrogen fluoride as a catalyst.[9] The purified dodecylbenzenes (and related derivatives) are then sulfonated with sulfur trioxide to give the sulfonic acid.[10] The sulfonic acid is subsequently neutralized with sodium hydroxide.[1] The term "linear" refers to the starting alkenes rather than the final product, perfectly linear addition products are not seen, in-line with Markovnikov's rule. Thus, the alkylation of linear alkenes, even 1-alkenes such as 1-dodecene, gives several isomers of phenyldodecane.[11] Structure property relationships Under ideal conditions the cleaning power of BAS and LABSA is very similar, however LABSA performs slightly better in normal use conditions, due to it being less affected by hard water.[12] Within LABSA itself the detergency of the various isomers are fairly similar,[13][14] however their physical properties (Krafft point, foaming etc.) are noticeably different.[15][16] In particular the Krafft point of the high 2-phenyl product (i.e. the least branched isomer) remains below 0 °C up to 25% LABSA whereas the low 2-phenyl cloud point is ∼15 °C.[17] This behavior is often exploited by producers to create either clear or cloudy products. Environmental fate Biodegradability has been well studied,[6][18][19] and is affected by isomerization, in this case, branching. The salt of the linear material has an LD50 of 2.3 mg/liter for fish, about four times more toxic than the branched compound; however the linear compound biodegrades far more quickly, making it the safer choice over time. It is biodegraded rapidly under aerobic conditions with a half-life of approximately 1–3 weeks;[18] oxidative degradation initiates at the alkyl chain.[1] Under anaerobic conditions it degrades very slowly or not at all, causing it to exist in high concentrations in sewage sludge, but this is not thought to be a cause for concern as it will rapidly degrade once returned to an oxygenated environment. LABSA Linear Alkyl Benzene Sulphonic Acid Product Information LABSA Linear alkyl benzene Sulphonic Acid is a chemical which is colorless and have viscous properties. LABSA Linear alkyl benzene sulphonic acid mainly using in detergent formulations. It is one of the most important and cheapest surfactants in powder formulation and detergent fluids. It has excellent cleansing properties. Usages of Linear Alkyl Benzene Sulphonic Acid LABSA Linear Alkyl Benzene sulphonic acid is a batch of organic sulfur compounds that are used in most home detergents, dishwashing detergents, detergent powder, cleaning powder, washing powders, detergent cake, liquid soap, soaps etc. LABSA, sulfonic acid compound is used as a foaming agent, cleaning agent in more formulations and toilet soaps for foaming. Sulfonic acid, LABSA is using in detergent industries, in textile industry as a washing agent, pesticides industries to improve the quality of spray. Sulfonic acid, LABSA is not inflammable substance and can dissolve in water, but not in organic solvent. Application of Linear Alkyl Benzene Sulphonic Acid Linear alkyl benzene Sulphonic Acid used in the industry to increase the contact of polar and non-polar phases, such as oil, water, or water and minerals. Linear alkyl benzene Sulphonic Acid sulfonate is mainly used for the manufacture of household detergents such as laundry powder, washing liquid, dishwashing liquid and other household cleaners and other industrial uses. LABSA Linear alkyl benzene Sulphonic Acid uses in produce sulfonic acid. LABSA is an additive as a lubricating agent oils and have as corrosion and rust prevention. his product is a very effective intermediate surfactant. Specification of Linear Alkyl Benzene Sulphonic Acid Product Name: Linear Alkyl benzene Sulphonic Acid ROW Characteristi LABSA Linear alkyl benzene Sulphonic Acid packing Basekim Chemical Production can supply LABSA Linear alkyl benzene Sulphonic Acid with drum. Each drum can take 220 kg and 80 drum can easily load in a container. It also depends on customer demands as well. LABSA Linear alkyl benzene Sulphonic Acid LABSA Linear alkyl benzene Sulphonic Acid is a chemical which is colorless and have viscous properties. LABSA Linear alkyl benzene Sulphonic Acid mainly using in detergent formulations. It is one of the most important and cheapest surfactants in powder formulation and detergent fluids. It has excellent cleansing properties. LABSA Linear alkyl benzene Sulphonic Acid in the formulation of anionic, non-anionic, and amphoteric surfactants, and it is extremely important for its degradability in nature. It is soluble in water and emulsifying agent. Linear Alkyl benzene sulphonic acid is one of the most widely used anionic surfactants due to its low cost, high efficiency and biocompatibility due to its linear chain. This anionic surfactant has hydrophilic and hydrophobic groups. These are non-volatile compounds produced by the sulfonation process. These compounds consist of mixtures of carbon chains of 10 to 14 carbon lengths that are a phenyl group with a sulfonate group LABSA Linear alkyl benzene Sulphonic Acid LABSA Linear alkyl benzene Sulphonic Acid application The properties of LABSA Linear alkyl benzene Sulphonic Acid depend on the length of the alkane chains that give them different functionality. Surfactants are used in the industry to increase the contact of polar and non-polar phases, such as oil, water, or water and minerals. Linear alkyl benzene Sulphonic Acid sulfonate is mainly used for the manufacture of household detergents such as laundry powder, washing liquid, dishwashing liquid and other household cleaners and other industrial uses. LABSA Linear alkyl benzene Sulphonic Acid uses in produce sulfonic acid. LABSA is an additive as an lubricating agent oils and have as corrosion and rust prevention. his product is a very effective intermediate surfactant. It is usually neutralized with alkali types and forms sulphonates used in different fields. This product can be used in acidic environments. LABSA Linear alkyl benzene Sulphonic Acid packing can supply LABSA Linear alkyl benzene Sulphonic Acid with drum . Each drum can take 220 kg and 80 drum can easily load in a container LABSA Linear alkyl benzene Sulphonic Acid PACKING Linear Alkyl Benzene Sulphonic Acid (LABSA) Specification LABSA properties: Trade Name: Sulfonic Acid COMMITTEE FOR VETERINARY MEDICINAL PRODUCTS LINEAR ALKYL BENZENE SULPHONIC ACIDS SUMMARY REPORT (1) 1. Linear alkyl benzene sulphonic acids (LABSA) are anionic surfactants. Linear alkyl benzene sulphonic acids are a mixtures of benzene sulphonic acids containing linear alkyl chains of different lengths (C9: less than 1%, C10: 8 to 16%, C11: 26 to 38%, C12: 26 to 38%, C13: 15 to 27% and longer than C13: less than 2.5%). The amount of linear alkyl benzene sulphonic acid in the products is 2% and these products are indicated for post-dipping or teat-spraying of dairy cows. The average dose per teat is assumed to be about 1 ml of the product, which equals to 80 mg of linear alkyl benzene sulphonic acid per cow per milking. Linear alkyl benzene sulphonic acids are commonly used as cleaning agents (household and personal care products). Linear alkyl benzene sulphonic acid is included as surface active agent in Commission establishing an inventory and a common nomenclature of ingredients employed in cosmetic products. The occupational and environmental exposure to linear alkyl benzene sulphonic acid has been assessed by WHO in 1996: The worldwide consumption of linear alkyl benzene sulphonic acids in 1990 was about 2 million tonnes. Linear dodecyl benzene sulphonic acid, under the synonym sodium dodecyl benzene sulphonate, has been included in 1987 on the food additive list of the Food and Drug Administration (FDA) of the United States of America as a surface active agent in commercial detergents used in washing fruits and vegetables or to assist in lye peeling these products. The tolerance limit has been set on equal to or less than 0.2% in wash water. 2. Hydrophobic and hydrophilic groups of the molecule are both essential for action of surfactants in detergents. According to a published study on the in vitro germicidal activity of teat dips the linear alkyl benzene sulphonic acid-containing product (1.94%) was shown to be completely effective against suspensions of Escherichia coli, Staphylococcus aureus and Streptococcus agalactiae containing bacteria/ml each following a contact time of 2 minutes. According to a published review document on in vitro studies, the 50% haemolytic concentration for linear alkyl benzene sulphonic acid was 9 mg/l and the 50% inhibitory concentration for prothrombin time was 0.05 mmol/l (16.3 mg/l). Linear alkyl benzene sulphonic acid influenced the thermal denaturation of proteins in vitro indicating protein-linear alkyl benzene sulphonic acid interaction. 3. Pharmacokinetic data are presented based on published reports. In rats, 14C-labelled alkyl benzene sulphonate was administered daily in the diet at a concentration of 1.4 mg/kg feed (dose per kg bw not given) to 12 male Wistar rats (120 to 140 g) for 5 weeks. Radioactivity was mostly excreted in faeces (52%) and in urine (29%) during the 5-week feeding period. After a single intraperitoneal administration of 14C-labelled alkyl benzene sulphonate (384.7 µg/rat), 85% of the dose was excreted during the first 24 hours and 95% within 10 days follow-up period. The main elimination route was via urine (50% of radioactivity), while 35% was excreted into faeces. However, during days 2 to 10 the percentage of radioactivity excreted into faeces was higher than that excreted into urine. No parent compound could be detected in faeces or urine but radioactivity was found in polar metabolites which were not further characterised. In another study, 35S-labelled linear alkyl benzene Sulphonic Acid was administered to male albino rats (Charles River strain, 150 to 200 g bodyweight) as a single per oral dose of 0.6, 1.2, 8 and 40 mg/rat (3 to 5 rats/group). During the 3-day follow-up period, 40 to 58% of radioactivity was excreted in urine and 39 to 56% in faeces. In faeces, the proportion of parent compound was 19% of total radioactivity. About 70% of linear alkyl benzene Sulphonic Acid was absorbed after oral administration. Two urine metabolites chemically close to methyl 4-(4'-methylsulfophenyl)- pentanoate were identified and were found to be a mixture of sulfophenyl butanoic acids and sulfophenyl pentanoic acids. Decomposition of linear alkyl benzene Sulphonic Acid sulphonate in rats was suggested to occur by ϖ-oxidation followed by catabolism through a β-oxidation mechanism. In vitro studies have not shown any penetration of 14C-labelled linear alkyl benzene sulphonic acid through intact rat or human skin. In in vivo studies in rats, 0.2 ml of 3 mM 14C linear alkyl benzene sulphonic acid (equivalent to 250 µg) was applied on 7.5 cm2 area of skin. These studies revealed deposition of 14C-labelled linear alkyl benzene sulphonic acid on the skin surface and in the upper regions of the hair follicles, however, no penetration of the substance could be detected after an exposure of 15 minutes. 4. The oral toxicity of linear alkyl benzene sulphonic acid is not very high. LD50 values for rats and mice range from 404 to 1525 mg/kg bw and 1575 to 1950 mg/kg bw, respectively. Both species showed diarrhoea and death occurred within 24 hours. 5. Repeated dose toxicity have been carried out using linear alkyl benzene sulphonic acids or their sodium salts containing alkyl chains of different lengths. Repeated dose toxicity has been documented on rats using 5 published articles, one of which was done in rats (60 females and 60 males/group) using only 1 dose level (0 and 100 mg of linear alkyl benzene sulphonic acid (chain length varying between C10 to C14)/l drinking water for 100 weeks). No differences were seen between test and control groups. No NOEL can be established due to deficiencies in the study design. Wistar rats (about 150 g, 10 per sex and group) received the test product (dishwashing detergent containing linear alkyl benzene sulphonic acid) was mixed into drinking water at corresponding to 0, 0.015, 0.075 and 0.375 ml linear alkyl benzene sulphonic acid/kg bw for 6 months. In the 3rd group the dose was increased after 9 weeks to 0.563 and again after 8 weeks to 0.75 ml/kg bw for 9 weeks. No differences were seen in haematological urine examinations between control and treated animals. Males showed decreased weight gain in the 3rd dose group, but the change was reversible once the treatment was stopped. Organ weights of the third group animals (5 per sex) killed immediately after the treatment were lower than those of the controls. Only control and the 3rd treatment groups were examined histologically. The animals in 3rd treatment group had small petechial bleedings (kidney, myocardium, lungs) and mucosal necrotis spots in gastrointestinal canal. They also had massive atrophy in adrenal glands and some atrophy in thymus. It is not possible to assess if changes showed correlation with dose or not, because only highest group was studied. No NOEL can be drawn from the study due to limited data available. Albino rats (FDRL strain, 15 animals per sex and group) received linear alkyl benzene sulphonic acid in feed at 0, 50 and 250 mg/kg bw for 12 weeks. Growth responses and food intake, haematological and urinary examinations showed no abnormalities. Histological findings revealed no abnormalities in lower dose group compared with control. Females in higher dose group had higher liver weight to body weight ratio than controls (p<0.01). The lower dose-group of 50 mg/kg bw/day showed no treatment-related changes. No NOEL can be established due to limited data available. Sprague-Dawley rat (10 animals per sex and group) received linear alkyl benzene sulphonic acid in feed (0, 0.02, 0.1 and 0.5%) for 90 days (corresponding to 8.8, 44 and 220 mg/kg bw). No statistically significant differences were seen in weight gains, food utilisation, haematological and urinary examinations. Organ to body ratios as well as macroscopic and microscopic findings were comparable in treated and control groups. No NOEL can be established due to limited data available. Charles River rat (50 animals per sex and group) received linear alkyl benzene sulphonic acid in feed (0, 0.02, 0.1 and 0.5%) for 2 years (dose per kg bw is not given). No statistically significant differences were seen in weight gains and food utilisation during the first 12 weeks. Organ to body ratios did not show any statistically significant differences when control and highest dose group were compared. At 8 months, male rats in 0.02 and 0.1% group had lower liver weight to bw ratios but this was not seen at later time points and never in the highest dose group. Haematological examinations revealed no treatment related changes. No abnormal macroscopic findings were seen and microscopic findings did not differ between the groups. No NOEL can be established due to limited data available. The highest dose (0.5% in feed for 2 years) did not show any treatment-related changes. A published repeated dose toxicity study has been carried out using 6 to 7 months old Beagle dogs (2 animals per sex and group). A linear alkyl benzene sulphonic acid-containing product (15% linear alkyl benzene sulphonic acid) was administered in doses of 0, 10, 100 and 1000 mg/kg bw daily for 6 months by gavage (corresponding to 0, 1.5, 15, and 150 mg linear alkyl benzene sulphonic acid/kg bw). Lowest dose group showed no treatment-related changes. One female dog in middle dose level group had drooling from the second week forward and one animal regurgitated part of one dose which lead to sedation and decreased appetite. In the highest dose group, 3 to 4 animals had marked salivation. No animals died. In the highest dose group feed intake was moderately reduced. Marked reduction in weight gain was only seen in the highest dose group (more pronounced in females). No changes were seen in blood and urinary tests. Eyes and hearing were normal in all groups. In highest dose group mucosal erosions were found in stomach (mainly in cardia) of one male and one female. Presence of haemosiderosis in spleen was more pronounced in highest dose group. One dog in the same group had small necroses in pancreas and 2 dogs had some iron-free pigment in kidneys. No NOEL can be established due to small number of animals and limited data available. According to a WHO report, minimal effects, including biochemical and histopathological changes in the liver, have been reported in subchronic studies in which rats were administered linear alkyl benzene sulphonic acid in the diet or drinking water at concentrations equivalent to doses greater than 120 mg/kg bw per day. These changes appeared to be reversible. In the absence of the original data, no firm conclusion on the data reported in the WHO report can be drawn. 6. Tolerance in dairy cows was studied using commercial teat dip containing 2% linear alkyl benzene sulphonic acid. The product was used post-milking twice daily for 10 days. The product was well-tolerated. 7. Effects on reproduction have been documented using 2 published articles, one of which described a study in rats (10 females and 10 males/group) using only one dose level of linear alkyl benzene Sulphonic Acid sulphonic acid (0 and 100 mg/l drinking water). The data provided are too limited for the assessment. Charles River rat (20 males and 20 females/group) received linear alkyl benzene sulphonic acid in feed (0, 0.02, 0.1 and 0.5% daily) in the 3-generation study (dose per kg bw is not given). No gross abnormalities were noted in pups. Rats of the F1 and F2 generations had similar growth patterns and organ to body weight ratios in control and test groups. No abnormalities were seen in histological examinations. In haematological studies, a statistically significant difference (level of significance not indicated) was seen in red blood cell count between control and females of highest test group. F3-weanlings were normal with respect to growth, organ to body weight ratios, macroscopic and microscopic examinations. Haematological values showed no treatment related trend or pattern in this study. The studies provided showed no indication of any reproduction toxicity. 8. Teratogenicity data were available from studies conducted using different linear alkyl benzene Sulphonic Acid sulphonic acids in mouse, rat and rabbit using oral, dermal and subcutaneous administration published in five articles. In two mouse studies the exposure times are not in accordance with the present guidelines. One study in mouse using dermal or subcutaneous administration was carried out using smaller group sizes and exposure times other than recommended in present guidelines. Linear alkyl benzene sulphonic acid (0, 0.2, 2, 300 and 600 mg/kg bw daily) was administered orally to female mice (n = 20), rats (n = 20) (days 6 to 15 of gestation) and rabbits (n = 13) days 6 to 18 of gestation). In all species primary toxic effects in dams were generally associated with disturbance of the gastrointestinal tract (diarrhoea, anorexia, retarded weight gain, weight loss, death). Rabbits were found to be the most susceptible species followed by mice and rats. The two highest dose groups showed maternal toxicity in mice and rabbits resulting in increased foetal loss and reduced litter size. No effects were seen in dams at 2 mg/kg bw in mice and rabbits. In rats, the highest dose caused maternal toxicity also, but did not affect litter parameters. No dose-related trend was seen in foetal weights. No difference was seen in number of major malformations between treated groups and controls. In mice, minor skeletal abnormalities increased to 33.7% in 300 mg/kg bw group compared with 11.7 to 13.3% in controls and lower dose groups. No teratological changes different from controls were seen except an increase in minor skeletal anomalies in 300 mg/kg bw group in mice. From the highest dose group no viable young were available as a result of marked maternal toxicity. When dermal exposure (linear alkyl benzene sulphonic acid in water) was used in mouse, rat and rabbit, the two highest doses caused severe skin reactions in mice (50 and 500 mg/kg bw) and rabbits (9 and 90 mg/kg bw). The highest dose in rats (60 mg/kg bw) showed also skin irritation: erythema and oedema with peak response on days 4 to 5. Except for the highest dose group in mice, no treatment related effects were seen in dams and litter data. In mice, a significant (p<0.05) increase in embryonic deaths was seen at 50 and 500 mg/kg bw compared with controls. In rats, no significant changes in litter parameters were seen in treated animals. In rabbits, the highest dose group had somewhat higher foetal loss and smaller litter size (statistically not significant). No statistically significant differences in anomalies were seen. The studies provided showed no indication of any teratogenic potential of the substanc