Maleic acid

116.07

116.07

605762

203-742-5

91XW058U2C

1186

25940

2215|3261

DTXSID8021517|DTXSID6051227|DTXSID2044008

C25951

Monoclinic prisms from water|White crystals from water, alcohol and benzene|Colorless crystals

29173990

74.60000

-0.01

White Powder/Solid

1.590 g/cm³ @ Temp: 20 °C

131 °C

110 °C

127 °C

1.526

H2O: 790 g/L (25 ºC)

Store at RT.

1.34X10-5 mm Hg at 25 deg C (OECD Guideline 104 (Vapor Pressure Curve))

4.0 (Air = 1)

Faint acidulous odor

Characteristic repulsive, astringent taste

1.83None

Henry's Law constant = 1.4X10-12 atm-cu m/mol at 25 °C (est)

1.83|pKa1 = 1.94, pKa2 = 6.22 at 25 °C (OECD Guideline 105)

112.5 Ų [M-H]-

Heat of combustion: -1356.3 kJ/mol (crystal)|Heat of combustion: -2,800 cal/g = -117x10+5 J/kg|log Kow = -1.3 at pH 2.5 and 20 °C|Hydroxyl radical reaction rate constant = 7.95X10-12 cu cm/molecule-sec at 25 °C (est)|Ozone reaction rate constant = 8.8X10-19 cu cm/molecule-sec at 25 °C (est)

Soluble in water.

Acids, Carboxylic

MALEIC ACID is a colorless to white crystalline solid. Moderately toxic. When heated to decomposition it emits irritating fumes and acrid smoke [Lewis, 3rd ed., 1993, p. 790].

-1355.2 kJ/mol

May corrode metals when wet.

III

8

3261

1

22-36/37/38-43

26-28-37-28A-46-24

OM9625000

Xn

Provision to contain effluent from fire extinguishing. Separated from food and feedstuffs. Dry.

Stable. Combustible. Incompatible with strong oxidizing agents, bases.

P280-P301 + P312 + P330-P305 + P351 + P338 + P310

H302 + H312-H315-H317-H318-H335

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.|/Product/ Offer surplus and non-recyclable solutions to a licensed disposal company. /Contaminated packaging/ Dispose of as unused product.

Oxidizing agents

Maleic acid is an indirect food additive for use only as a component of adhesives.

Dangerous Prop Ind Mater Rep 7 (1): 61-5 (1987). A review of safety and the health hazards of maleic acid.

Special Hazards of Combustion Products: Irritating smoke containing maleic anhydride may form in fire. (USCG, 1999)|Combustible. Gives off irritating or toxic fumes (or gases) in a fire.

|Warning|H302: Harmful if swallowed [Warning Acute toxicity, oral]|P261, P264, P270, P271, P272, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P403+P233, P405, and P501|Danger|H290 (40.3%): May be corrosive to metals [Warning Corrosive to Metals]|P234, P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P337+P313, P363, P390, P404, P405, and P501|Aggregated GHS information provided by 134 companies from 11 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|H302 (98.93%): Harmful if swallowed [Warning Acute toxicity, oral]|P261, P264, P270, P271, P272, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P333+P313, P337+P313, P362, P363, P403+P233, P405, and P501|Aggregated GHS information provided by 1877 companies from 58 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|P261, P264, P270, P271, P272, P273, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P403+P233, P405, and P501|P260, P264, P270, P280, P301+P312, P302+P352, P305+P351+P338, P307+P311, P310, P312, P321, P322, P330, P332+P313, P362, P363, P405, and P501

Excerpt from ERG Guide 156 [Substances - Toxic and/or Corrosive (Combustible / Water-Sensitive)]: As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. SPILL: Increase, in the downwind direction, as necessary, the isolation distance shown above. FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)

Excerpt from ERG Guide 156 [Substances - Toxic and/or Corrosive (Combustible / Water-Sensitive)]: ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. A vapor-suppressing foam may be used to reduce vapors. FOR CHLOROSILANES, use AFFF alcohol-resistant medium-expansion foam to reduce vapors. DO NOT GET WATER on spilled substance or inside containers. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Prevent entry into waterways, sewers, basements or confined areas. SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. (ERG, 2016)

Dust mask; goggles or face shield; protective gloves (USCG, 1999)|/Eye/face protection/ Face shield and safety glasses Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).|/NIOSH certified respirator/; goggles or face shield; protective gloves.|/Respiratory protection/ For nuisance exposures use type P95 (US) or type P1 (EU EN 143) particle respirator.For higher level protection use type OV/AG/P99 (US) or type ABEK-P2 (EU EN 143) respirator cartridges. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).|/Body Protection/ Complete suit protecting against chemicals. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.|/Skin protection/ Handle with gloves.

Combustible when exposed to heat or flame.

Wear self-contained breathing apparatus for firefighting if necessary.|Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Irritating smoke containing maleic anhydride may form in fire.

Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.|Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.|ACCIDENTAL RELEASE MEASURES /Personal precautions, protective equipment and emergency procedures/ Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.|SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.|Local exhaust.|Further processing of solid materials may result in the formation of combustible dusts. The potential for combustible dust formation should be taken into consideration before additional processing occurs. Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed.|For more Preventive Measures (Complete) data for MALEIC ACID (6 total), please visit the HSDB record page.

Passes through intact skin. A skin and severe eye irritant and a corrosive.|Dust: Irritating to eyes, nose and throat. ... Solid: Irritating to skin and eyes.

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Wash away remainder with plenty of water.

Provision to contain effluent from fire extinguishing. Separated from food and feedstuffs. Dry. Store only in original packaging.

Evaporation at 20 °C is negligible; a harmful concentration of airborne particles can, however, be reached quickly when dispersed, especially if powdered.

The substance is severely irritating to the eyes. The substance is irritating to the skin and respiratory tract.

Repeated or prolonged contact with skin may cause dermatitis. Repeated or prolonged contact may cause skin sensitization.

NO open flames.

PREVENT DISPERSION OF DUST! STRICT HYGIENE!

Use local exhaust or breathing protection.

Protective gloves. Protective clothing.

Wear safety goggles or eye protection in combination with breathing protection.

This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. Maleic acid is produced, as an intermediate or a final product, by process units covered under this subpart.

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 5000 lb or 2270 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV.D.3.b).

Motor exhaust of two automobiles (1982 Toyota Corolla, 1972 Mercedes Benz) contained 22.9 and 219.8 nmol/cu m of maleic acid(2). Aerosol samples collected from a Hong Kong roadway tunnel during 2003-2004 monitoring contained maleic acid levels of 4.0-22.3 ng/cu m(2); apparent occurence of maleic acid was reported as 2.70-5.61 ug/vehicle-km(2).

Two soil samples taken at the University of California, Los Angeles campus contained ND (not detected) and 2.33 nmol/g of maleic acid, whereas bog sediment samples from the Sierra Nevada foothills contained 8 nmol/g(1). Maleic acid was qualitatively detected in German soil samples(2).

URBAN/SUBURBAN: The concentration of maleic acid in aerosol samples from West Los Angeles and Los Angeles were 9-204 and 64-95 ng/cu m, respectively(1); two dust samples collected from the balcony of the UCLA geology building contained 6.4 and 2.4 ppm of maleic acid, respectively(1). Aerosol samples collected in Tokyo Japan in 1992 contained maleic acid concentrations of 21-33 ng/cu m(2). Maleic acid was detected in PM2.5 atmospheric aerosol samples collected from the southeastern US in the summer of 2003(3). Urban aerosol samples collected in Tokyo Japan during 1988-1989 monitoring contained an average maleic acid concentration of 5.6 ng/cu m (maximum of 17 ng/cu m)(4). Analysis of 27 atmospheric aerosol samples detect a maleic acid concentration range of 4.3-29.0 ng/cu m with a mean concentration of 10 ng/cu m(5). Aerosol samples (PM2.5) collected in Nanjing China between July 2004 and January 2005 contained mean maleic acid concentrations of 37.7-42.2 ng/cu m during daytime and 27.7-41.7 ng/cu during nightime(6).|RURAL/REMOTE: Arctic aerosol samples collected from Alert, Canada during 1987-1988 contained a mean maleic acid concentration of 0.19 ng/cu m with a range of 0.016-0.61 ng/cu m(1); elevated diacid levels occurred during extended sunlight times, as opposed to dark periods, suggesting the presence of the diacids (such as maleic acid) was due to photooxidation generation from other atmospheric compounds(1).|RAIN/SNOW: Snow, sleet and rain samples collected in Tokyo Japan in 1992 contained maleic acid concentrations of 0.46-48.4 ug/L(1).

Maleic acid has been identified as a component of tobacco smoke(1).

IDENTIFICATION AND USE: Maleic acid forms colorless or white crystals. It is used for manufacturing of artificial resins, dyeing and finishing wool, and for preparing the maleate salts of antihistamines and similar drugs. HUMAN EXPOSURE AND TOXICITY: A 20% aqueous solution produced a mild and reversible skin irritation in humans. Lower concentrations (< 5%) are sufficient to produce serious ocular irritation in human subjects. Neat maleic acid is reported to be a severe irritant to the mucous membranes of humans. In vitro, maleic acid produced highly significant alterations in the physical state of human erythrocyte membrane proteins. ANIMAL STUDIES: Single intravenous application of 400 or 200 mg/kg bw maleic acid to male rats via jugular venous catheter caused immediate injury in the kidneys which progressed to extensive necrosis by 24 hr after administration. In dogs the intravenous administration of maleic acid (50 mg/kg) increased sodium, potassium, and phosphate excretion. Maleic acid may enhance anaphylactic histamine release from guinea pig lung by its metabolic utilization in the tricarboxylic acid cycle. Kidney damage has been observed as a systemic toxic action of maleic acid. Morphological-functional changes in the kidneys were produced by intraperitoneal injection (100-350 mg/kg; rats, dogs) and also by inhalation exposure to ca. 720 mg/mc (rats). The damage to distal and proximal tubular resorption produced by maleic acid is reminiscent of the known (congenital or acquired) Fanconi syndrome in humans. This damage seems to be caused by the interaction of maleic acid with glutathione in tubular renal cells, leading to intolerable concentration of free radicals and peroxides. In addition to the resultant cellular damage, maleic acid appears to affect Na+ and H+ ion transport in the proximal tubes. After chronic exposure of male rats (250, 500, 750 mg/kg /per/ day for up to two years), an increased mortality as well as kidney damage and delayed growth was observed in all dosage groups. Liver and testicular damage has also been found in highest dosage group. No signs of carcinogenic activity of maleic acid were discovered with long-term dosage, which however was not designed as a carcinogenicity study. Maleic acid given to mice has some inhibitory action on the growth of spontaneous carcinomata and grafted sarcomata. When tested using Salmonella typhimurium TA100, maleic acid was not mutagenic when reacted with chlorine in aqueous solution. In a 50/50 by vol methanol/water solution it was substantially mutagenic, and reacted with chlorine with a peak at 3 equivalents per mole.

Maleic acid was administered iv both alone and after initiating iv administered neutral sodium phosphate, sodium sulfate, or sodium chloride to 10 unanesthetized trained female dogs undergoing water diuresis. /The following observations were noted:/ 1) Administration of maleic acid alone predictably induced dose-dependent increments in urine flow and in renal clearance of HCO3-, Na+, K+, and alpha-aminonitrogen and a pronounced increase in the renal clearance and excretion of citrate. 2) Prior phosphate loading, which increased the plasma concentration of phosphate from 2.5 +/- 0.20 to 11.3 +/- 2 mg/dL: a) attenuated the increment in renal clearance of HCO3 by one-half even though the filtered load of bicarbonate was higher by 37%, owing to the higher values of both GFR and plasma bicarbonate concentration that obtained with phosphate loading; b) prevented the increment in renal clearance and excretion of alpha-aminonitrogen; c) significantly attenuated the increments in urine flow and renal clearance of K+; but d) did not affect the increment in renal clearance and excretion of citrate.|The admin of maleic acid (100 mg/kg) to rats which were infused with acetoacetic acid (200 mM at 0.1 mL/min) did not induce phosphaturia or calciuria, whereas maleic acid given alone was phosphaturic & calciuric. There was a significant decrease of the phosphate & calcium excretion in maleic acid-treated rats after the iv injection of 150 pg 1,25-dihydroxyvitamin D3 in comparison with the control group.|Groups of male and female Sprague Dawley rats (n = 4 to 8 for each sex) were admin either maleic acid (150 mg/kg, sc), dichloromaleic acid (100, 200, 300, or 400 mg/kg, ip) or their combination. Urine was collected at 24 hr intervals. In both males and females, dose dependent declines in food and water consumption as well as body wt and urine flow were observed at 24 hr post-treatment with maleic acid, dichloromaleic acid, or dichloromaleic acid + maleic acid. Sc administration of maleic acid at a dose of 150 mg/kg had no effect on several parameters of renal function in either sex at 24 hr and only modest effects at 48 hr. Maleic acid alone had no effect on renal organic ion accumulation in either sex. The combination of maleic acid + dichloromaleic acid caused a depression of tetraethylammonium accumulation in renal slices from females. Also changes in urinary glucose excretion and blood urea nitrogen, although additive in the male following coexposure, appeared synergistic or potentiated in the female. For females, maleic maleic alone produced a greater response in urinary glucose than control, and the combination resulted in a significantly exaggerated response at 24 hr. There were not significant alterations in urinary glucose in the male at 24 hr after any dosages. Both p-aminohippurate and lactate stimulated p-aminohippurate transport were impaired in the female with either dichloromaleic acid or dichloromaleic acid + maleic acid and to a significantly greater extent than in the male. Triethanolamine accumulation in the female declined significantly when exposed to dichloromaleic acid + maleic acid, an effect not observed in the male.|At all doses of maleic acid (600, 300, 150 mg/kg bw), structural damage of the proximal renal tubule was much greater in rats fed with supplemental glucose.

LD50 Rat oral 708 mg/kg|LD50 Mouse oral 2400 mg/kg|LD50 Rabbit dermal 1560 mg/kg

Maleic acid is reported to occur in ginseng, tobacco leaf, sour cherry fruit, cacao plant and corn plant(1). Maleic acid has been identified as a photooxidation product of biogenic compounds occurring in the ambient atmosphere (such as d-limonene) with the product becoming associated with atmospheric aerosol(2).

Maleic acid's production and use in organic synthesis (to produce a variety of acids), in the dyeing and finishing of cotton, wool and silk, as a preservative for oils and fats(1), in the manufacture of artificial resins and in the preparation of maleate salts of drugs(2) may result in its release to the environment through various waste streams(SRC). Maleic acid is released directly to the environment in motor vehicle exhaust(3,4) and as a component of tobacco smoke(5). Maleic acid may be formed in the atmosphere via hydrolysis of anthropogenic releases or formation of maleic anhydride(6).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 7(SRC), determined from a structure estimation method(2), indicates that maleic acid is expected to have very high mobility in soil(SRC). The pKa values of maleic acid are 1.94 and 6.22(3), indicating that this compound will exist almost entirely in anion from in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Volatilization of maleic acid from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.4X10-12 atm-cu m/mole(SRC), using a fragment constant estimation method(2). Maleic acid is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.34X10-5 mm Hg at 25 °C(3). Results of several screening tests indicate that maleic acid is readily biodegradable(3,5), and therefore, biodegradation is expected to be an important fate process in soil(SRC). Maleic acid reached 87% of its theoretical BOD in 2 weeks in the Japanese MITI test(5).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 7(SRC), determined from a structure estimation method(2), indicates that maleic acid is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 1.4X10-12 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). The pKa values of 1.94 and 6.22(4) indicate maleic acid will exist almost entirely in anion form at pH values of 5 to 9 and ionization could attenuate potential volatilization from water surfaces(SRC). Although almost entirely in anion form, acids have been shown to have effective Henry's Law constants under environmental conditions(5). According to a classification scheme(6), a BCF of <10 measured in fish (golden ide)(7) suggests the potential for bioconcentration in aquatic organisms is low. Results of several screening tests indicate that maleic acid is readily biodegradable(4,8) and, therefore, biodegradation is expected to be an important fate process in water(SRC). Maleic acid reached 87% of its theoretical BOD in 2 weeks in the Japanese MITI test(8). Maleic acid is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(3).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), maleic acid, which has a vapor pressure of 1.34X10-5 mm Hg at 25 °C(2) will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase maleic acid is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2 days(SRC), calculated from its rate constant of 7.95X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Vapor-phase maleic acid is also degraded in the atmosphere by reaction with ozone(SRC); the half-life for this reaction in air is estimated to be 13 days(SRC), calculated from its rate constant of 8.8X10-19 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Maleic acid has been detected in numerous atmospheric aerosol samples(4-6). Particulate-phase maleic acid may be removed from the air by wet and dry deposition(SRC). The UV spectrum of maleic acid in water(7) indicates that the compound does not absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

The rate constant for the vapor-phase reaction of maleic acid with photochemically-produced hydroxyl radicals has been estimated as 7.95X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of maleic acid with ozone has been estimated as 8.8X10-19 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 13 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(1). The rate constant for the reaction of maleic acid with hydroxyl radicals in aqueous solutions at pH 4-10.5 is 6.0X10+9 L/mol-sec(2); this corresponds to an aquatic half-life of 116 days at an aquatic concentration of 1X10-17 hydroxyl radicals per liter(3). The UV spectrum of maleic acid in water(4) indicates that the compound does not absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC). When adsorbed on silica gel and irradiated with light near 290 nm for 17 hr, 17% of the maleic acid was reported to have mineralized(3); conditions of the test may not have correspondence to environment degradation(SRC). Maleic acid is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(6).

The BCF of maleic acid in fish (golden ide) was measured as <10 after 3 days of exposure(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC). The BCF in algae (Chorella fusca) was 11 after a 24 hour exposure period(1).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of maleic acid can be estimated to be 7(SRC). According to a classification scheme(2), this estimated Koc value suggests that maleic acid is expected to be very mobility in soil. The pKa values of maleic acid are 1.94 and 6.22(3), indicating that this compound will exist almost entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4).

The Henry's Law constant for maleic acid is estimated as 1.4X10-12 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that maleic acid is expected to be essentially nonvolatile from water surfaces(2). In addition, the pKa values of maleic acid are 1.94 and 6.22(3), indicating that this compound will exist almost entirely in anion form in the environment and that volatilization is not an important fate process(SRC). Although almost entirely in anion form, acids have been shown to have effective Henry's Law constants under environmental conditions with the partitioning from water to air decreasing with increasing pH(4). Maleic acid's Henry's Law constant indicates that volatilization from moist soil surfaces will not occur(SRC). Maleic acid is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.34X10-5 mm Hg(3).

Maleic acid was detected in foods, such as tapioca starch, tapioca balls, rice noodles, and hotpot ingredients which caused a recall of many starch-based food products in Asia(1). The occurrence of maleic acid in foods can result from modified starches containing maleic anhydride and hydrolysis of the maleic anhydride to maleic acid(1). Maleic acid was detected in alcoholic beverages produced by fermentation (beer and wine)(2).

According to the 2012 TSCA Inventory Update Reporting data, 6 reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of maleic acid in the United States may be as low as <10 workers and as high as 100-499 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).|NIOSH (NOES Survey 1981-1983) has statistically estimated that 30,064 workers (11,590 of these were female) were potentially exposed to maleic acid in the US(1). Occupational exposure to maleic acid may occur through inhalation and dermal contact with this compound at workplaces where maleic acid is produced or used. Monitoring data indicate that the general population may be exposed to maleic acid via inhalation of ambient air, inhalation of tobacco smoke, ingestion of food and alcoholic beverages, and dermal contact with consumer products containing maleic acid(SRC).

Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. (See all compounds classified as Enzyme Inhibitors.)

Kidney damage has been observed as a systemic toxic action of maleic acid. Morphological-functional changes in the kidneys were produced by intraperitoneal injection (100-350 mg/kg; rats, dogs) and also by inhalation exposure to ca. 720 mg/mc (rats). The damage to distal and proximal tubular resorption produced by maleic acid is reminiscent of the known (congenital or acquired) Fanconi syndrome in humans. This damage seems to be caused by the interaction of maleic acid with glutathione in tubular renal cells, leading to intolerable concentration of free radicals and peroxides. In addition to the resultant cellular damage, maleic acid appears to affect Na+ and H+ ion transport in the proximal tubes [RE5]. After chronic exposure of male rats (250, 500, 750 mg/kg /per/ day for up to two years), an increased mortality as well as kidney damage and delayed growth was observed in all dosage groups. Liver and testicular damage has also been found in highest dosage group. No signs of carcinogenic activity of maleic acid were discovered with long-term dosage, which however was not designed as a carcinogenicity study.

Inhalation causes irritation of nose and throat. Contact with eyes or skin causes irritation. (USCG, 1999)

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment. INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing. INGESTION: DO NOT INDUCE VOMITING. Corrosive chemicals will destroy the membranes of the mouth, throat, and esophagus and, in addition, have a high risk of being aspirated into the victim's lungs during vomiting which increases the medical problems. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. IMMEDIATELY transport the victim to a hospital. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. Transport the victim IMMEDIATELY to a hospital. (NTP, 1992)

Fresh air, rest. Refer for medical attention.

Wear protective gloves when administering first aid. Remove contaminated clothes. Rinse skin with plenty of water or shower.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Organic acids and related compounds/|Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist respirations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Activated charcoal is not effective ... . Do not attempt to neutralize because of exothermic reaction. Cover skin burns with dry, sterile dressings after decontamination ... . /Organic acids and related compounds/|Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Early intubation, at the first sign of upper airway obstruction, may be necessary. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Organic acids and related compounds/

/SIGNS AND SYMPTOMS/ A 20% aqueous solution produced a mild and reversible skin irritation in humans.|/SIGNS AND SYMPTOMS/ Lower concentrations (< 5%) are sufficient to produce serious ocular irritation /in human subjects/.|/SIGNS AND SYMPTOMS/ Neat maleic acid is reported to be a severe irritant to the mucous membranes of humans.|/ALTERNATIVE and IN VITRO TESTS/ In vitro, maleic acid produced highly significant alterations in the physical state of human erythrocyte membrane proteins.|/OTHER TOXICITY INFORMATION/ Aged aq soln of either substance /maleic acid or maleic anhydride/ exhibit equal toxicity owing to conversion of the anhydride to acid by reaction with water.

hydrogen maleate

The substance can be absorbed into the body by inhalation and by ingestion.

Cough. Laboured breathing.

Redness. Pain.

Redness. Pain. Blurred vision.

Grades of purity: Reagent; Technical

All other basic organic chemical manufacturing|2-Butenedioic acid (2Z)-: ACTIVE|Paper manufacturing|2-Butenedioic acid (2Z)-, homopolymer: ACTIVE|XU - indicates a substance exempt from reporting under the Chemical Data Reporting Rule, (40 CFR 711).|2-Butenedioic acid (2Z)-, monocastor oil alkyl esters: INACTIVE|Maleic anhydride is readily hydrolyzed to maleic acid under aqueous conditions. As a result, these two chemicals are presented because of the conditions used to test their toxicity. The only difference may be due to the potential for maleic anhydride to form haptens by acylating with amino acids, resulting in an immunological response (dermal and respiratory sensitization).|By-product from manufacture of phthalic anhydride from naphthalene with special recovery conditions.

The free maleic acid content in maleic anhydride is determined by direct potentiometric titration.|MALEIC ACID /WAS/ DETECTED IN AIR BY GC METHYLATION WITH BORON TRIFLUORIDE.|Maleic acid and timolol in mixtures & formulations containing timolol maleate were determined by HPLC. The eluate was monitored at 235 nm for 5 min & then at 294 nm. The detection limit was approx 500 pg, and accuracy was greater than 98%.|An ion chromatographic system was developed for routine measurement of carboxylic acids with carbon numbers up to C8 in precipitation samples. The system combines online sample preconcentration on a low capacity anion exchange resin with separation by ion exclusion and subsequent detection by UV absorption. Maleate anions, however, are hidden under the large peak of the strong mineral acids. Using mixtures of carboxylic acids likely to occur in the atmosphere, maleic acid was found to have a retention time of 12.0 min.

EPA Safer Chemical Functional Use Classes -> Polymers|Safer Chemical Classes -> Green circle - The chemical has been verified to be of low concern|Cosmetics -> Buffering|Environmental transformation -> Pesticide transformation products (metabolite, successor)

Maleic acid is a known environmental transformation product of Linuron.