チオ尿素

Fire Extinguishing Agents: Small fires: dry chemical, CO2, water spray or foam; large fires: water spray, fog or foam. (USCG, 1999)

Use water spray, foam, powder, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention .

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

Induce vomiting (ONLY IN CONSCIOUS PERSONS!). Refer for medical attention .

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.

Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Wear self-contained breathing appartus for fire-fighting if necessary.

Keep container tightly closed in a dry and well-ventilated place. Handle and store in inert gas. Storage class (TRGS 510): Non Combustible Solids.

Thiourea is packed in polyethylene bags (less than or equal to 50 kg) or in folding containers (less than or equal to 1500 kg). Bags and containers must be kept tightly closed, and in a cool, dry place. The contents must be protected from the action of light.

PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practicable to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired. ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/

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.

Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust.

Sludge was treated with 5% aq soln of thiourea, sand & portland cement at pH 12.5. Leaching test of resulting concrete showed that dissolved concn of mercury, cadmium,lead, copper, & arsenic were far below regulation levels.

For more Cleanup Methods (Complete) data for THIOUREA (6 total), please visit the HSDB record page.

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U219, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

A potential candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A potential candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.

The following wastewater treatment technology has been investigated for thiourea: Concentration process: Biological treatment.

PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... Summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/

For more Disposal Methods (Complete) data for THIOUREA (8 total), please visit the HSDB record page.

Evacuate danger area! Consult an expert! Personal protection: chemical protection suit and particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Do NOT wash away into sewer. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.

In the case of the precursor /to aminothiazole/, thiourea, particular attention should be given to the hazard of skin absorption by the provision of protective clothing and adequate sanitary facilities incl showers.

PRECAUTIONS FOR "CARCINOGENS": Smoking, drinking, eating, storage of food or of food & beverage containers or utensils, & the application of cosmetics should be prohibited in any laboratory. All personnel should remove gloves, if worn, after completion of procedures in which carcinogens have been used. They should ... wash ... hands, preferably using dispensers of liq detergent, & rinse ... thoroughly. Consideration should be given to appropriate methods for cleaning the skin, depending on nature of the contaminant. No standard procedure can be recommended, but the use of organic solvents should be avoided. Safety pipettes should be used for all pipetting. /Chemical Carcinogens/

PRECAUTIONS FOR "CARCINOGENS": ... Operations connected with synth & purification ... should be carried out under well-ventilated hood. Analytical procedures ... should be carried out with care & vapors evolved during ... procedures should be removed. ... Expert advice should be obtained before existing fume cupboards are used ... & when new fume cupboards are installed. It is desirable that there be means for decreasing the rate of air extraction, so that carcinogenic powders can be handled without ... powder being blown around the hood. Glove boxes should be kept under negative air pressure. Air changes should be adequate, so that concn of vapors of volatile carcinogens will not occur. /Chemical Carcinogens/

PRECAUTIONS FOR "CARCINOGENS": Vertical laminar-flow biological safety cabinets may be used for containment of in vitro procedures ... provided that the exhaust air flow is sufficient to provide an inward air flow at the face opening of the cabinet, & contaminated air plenums that are under positive pressure are leak-tight. Horizontal laminar-flow hoods or safety cabinets, where filtered air is blown across the working area towards the operator, should never be used. ... Each cabinet or fume cupboard to be used ... should be tested before work is begun (eg, with fume bomb) & label fixed to it, giving date of test & avg air-flow measured. This test should be repeated periodically & after any structural changes. /Chemical Carcinogens/

For more Preventive Measures (Complete) data for THIOUREA (11 total), please visit the HSDB record page.

Changes of TSH-producing cells in the pituitary and thyroid expression of the growth factors, transforming growth factor alpha (TGF alpha) and epidermal growth factor receptor (EGFR), as well as cyclin D1, were investigated immunohistochemically in order to clarify their contribution to the enhancing effects of excess vitamin A (VA) on thyroidal carcinogenesis induced by thiourea (TU). Male rats were allocated to 4 groups, control, TU, VA, and TU + VA, respectively, receiving no treatment, water containing 0.2% TU, diet containing 0.1% VA, and both for 10 or 19 weeks after a single s.c. injection of DHPN (N-bis(2-hydroxypropyl)nitrosamine) (2800 mg/kg) for initiation. Immunohistochemistry using antibodies against TSH demonstrated enlargement of TSH-producing cells in the TU + VA group as compared to the TU group, supporting our conclusion that enhanced TSH stimulation is mainly responsible for promoting the effects of excess VA. Since the expression of TGF alpha, EGFR, and cyclin D1 in thyroid proliferative lesions did not exhibit any differences between the TU and TU + VA groups in the present study, these factors are unlikely to participate in VA enhancement of carcinogenesis.

In our previous investigation, which focused on two-stage carcinogenicity in the thyroid, rats were administered N-bis(2-hydroxypropyl)nitrosamine (DHPN), followed by thiourea (TU) over an experimental period of 19 weeks. Simultaneous treatment with a high level of vitamin A (VA) enhanced the induction of proliferative lesions that originated from the thyroidal follicular epithelium. To examine whether hormone synthesis in the thyroid could be inhibited by simultaneous treatment with a large amount of VA and TU, all of the rats were initially given a single subcutaneous injection of 2,800 mg DHPN/kg followed by a supply of 0% TU + 0% VA (DHPN only, control group), 0.2% TU in their drinking water (DHPN/TU group), 0.1% VA in their diet (DHPN/VA group), or 0.2% TU + 0.1% VA (DHPN/TU + VA group) during an experimental period of 4 weeks. Results obtained indicate that the iodine uptake and organification, namely iodination of tyrosine residue in thyroglobulin, of the thyroid, were significantly decreased in the DHPN/TU group compared to the DHPN control group. The variation in these values was attributable to the inhibitory effect of TU upon thyroid hormone synthesis. Results obtained from the DHPN/TU + VA and DHPN/TU groups were comparable. Therefore, the possibility that modification of hormone synthesis contributes to the enhancing effect of simultaneous treatment with a large amount of VA on thyroidal tumor induction by TU is considered to be very minimal.

Time course changes in serum TSH and quantitative data for thyroid proliferative lesions in male F344 rats administered N-bis(2-hydroxypropyl)nitrosamine (DHPN: 2000 mg/kg body weight, single s.c. injection) followed by 0.1% thiourea (TU), were assessed at weeks 1, 2, 4, 8, 12 and 16 of treatment. The serum T4 level in the TU group was markedly decreased at week 1 and remained significantly lowered throughout the experiment. Serum TSH levels, in contrast, were elevated up to a peak at around week 4 with a return to the normal range at week 12. Thyroid weights in the TU group were increased significantly in a treatment period-dependent manner. Histopathologically, marked hypertrophy of thyroid follicular cells occurred at the early stage of TU treatment. Proliferative lesions, such as hyperplasia and adenomas, occurred from weeks 2 and 4, respectively, and increased with the later treatment period. The cell proliferative activity of follicular cells, assessed by BrdU incorporation, was high until week 2, but then returned to normal. The initially appearing hyperplasias and adenomas were characterized by marked proliferation but this also greatly decreased at later stages when TSH was no longer elevated. The results of our study thus suggest that a high serum TSH level plays an important role in the early phase of thyroid tumorigenesis and 8 weeks treatment with test substances is sufficient for detection of thyroid tumor promoter potential in two-stage thyroid carcinogenesis models.

To evaluate the effects of phenobarbital (PB) and thiourea (TU), alone or in combination, on proliferative lesions of the liver, thyroid and lung, male F344 rats initiated with 2000 mg/kg body weight N-bis(2-hydroxypropyl) nitrosamine (DHPN) were given diet and/or drinking water containing 0% PB/TU (group 1), 1000 ppm PB (group 2), 0.1% TU (group 3) and 500 ppm PB and 0.05% TU (group 4), from weeks 2 to 20 for 19 weeks. Group 4 showed remarkable increases in the number of hepatocellular altered foci per animal, the values being superior to the averages of groups 2 and 3. The number of thyroid proliferative lesions per animal was highest in group 3 and lowest in group 2. Lung proliferative lesions were induced in all groups, but no modifying influence on their development was evident in the combined group. The present results indicate that combined administration of PB and TU exerts synergistic enhancing effects on hepatocarcinogenesis.

For more Interactions (Complete) data for THIOUREA (24 total), please visit the HSDB record page.

EC50; Species: Scenedesmus abundans (Green algae) 10+4 cells/mL; Conditions: freshwater, static, 22 °C; Concentration: 4800 ug/L for 96 hr; Effect: inhibition of cell growth /99.5% purity/

LC50; Species: Daphnia magna (Water flea) age <24 hr; Conditions: freshwater, static, 20 °C, pH 8.2, hardness 250 mg/L CaCO3, dissolved oxygen >6.5 mg/L; Concentration: 9000 ug/L for 48 hr (95% confidence interval: 5600-18000 ug/L) />99% purity/

TERRESTRIAL FATE: Based on a classification scheme(1), a measured Koc range of 7-36(2,3) indicates that thiourea is expected to have very high mobility in soil(SRC). Volatilization of thiourea from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.1X10-13 atm-cu m/mole(SRC), derived from its vapor pressure, 1.41X10-7 mm Hg(4), and its water solubility, 1.34X10+5 mg/L(5). Thiourea is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Utilizing the Japanese MITI test, 2.6% of the Theoretical BOD was reached in 2 weeks indicating that thiourea is not readily biodegradable(6). However, water, sediment and soil degradation studies have indicated that thiourea is biodegradable(2,7). In aerobic batch laboratory microcosm experiments, thiourea half-lives of 12.8 days (basic soil) and 18.7 days (acid soil) were determined(2,7), however, no abiotic controls were performed, and removal of thiourea was attributed mainly to biotic processes(2). Elevated thiourea concentrations may be toxic to microorganisms and inhibit biodegradation(2,7).

AQUATIC FATE: Based on a classification scheme(1), a measured Koc range of 7-36(2,3) indicates that thiourea is not expected to adsorb to suspended solids and sediment in water(SRC). Volatilization from water surfaces is not expected(4) based upon an estimated Henry's Law constant of 1.1X10-13 atm-cu m/mole(SRC), derived from its vapor pressure, 1.41X10-7 mm Hg(5) and water solubility, 1.34X10+5 mg/L(6). According to a classification scheme(7), a measured BCF of <2 in carp (Cyprinus carpio)(8) suggests the potential for bioconcentration in aquatic organisms is low. Die-away studies using freash and saltwater observed slow but continuous degradation of thiourea over the incubation period of 85 days (maximum 9% within the first 8 days, maximum 68% at the end of observation based on carbon dioxide production)(9); in sediment samples, 40-70% degradation was observed(9). The die-away tests demonstrate that thiourea serves as nitrogen source for degrading microorganisms with thiourea more easily biodegraded in nitrogen-limited environments(2). Thiourea may be degraded slowly in water by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in natural water is estimated to be 206 days(SRC), calculated from its rate constant of 3.9X10+9 L/mol-sec(10). Thiourea is hydrolytically stable(9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), thiourea, which has a vapor pressure of 1.41X10-7 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase thiourea 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 9 hours(SRC), calculated from its rate constant of 4.2X10-11 cu cm/molecule-sec at 25 °C(SRC) determined using a structure estimation method(3). Particulate-phase thiourea may be removed from the air by wet and dry deposition(SRC). In methanol solution, the ultraviolet absorption spectrum of thiourea shows weak absorption from 290 to 310 nm with no absorption above 310 nm(4), and therefore, may be susceptible to direct photolysis by sunlight(SRC).

IDENTIFICATION AND USE: Thiourea occurs as white, lustrous crystals or flaky solids. It is not registered for current pesticide use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses. It has many uses including for photography and photocopying papers, organic synthesis of dyes, drugs, and hair preparations, rubber accelerators, analytical reagents, amino resins, mold inhibitors, flame retardants for textiles, peptizing agents, pesticides, chelating agents, and as a reagent for bismuth and selenite ions. Other uses are as an additive for slurry explosives, as a viscosity stabilizer for polymer solutions (e.g., in drilling muds), and as a mobility buffer in petroleum extraction. The removal of mercury from wastewater from chlorine-alkali electrolysis and gold and silver extraction from minerals are also of economic importance. Thiourea has been identified as being used in hydraulic fracturing as a corrosion inhibitor. HUMAN EXPOSURE AND TOXICITY: The primary routes of potential human exposure to thiourea are inhalation and dermal contact. The greatest risk of potential exposure exists for workers involved in the production or use of thiourea. Thiourea has been identified as a sensitizer in people suffering from photosensitivity. It may also cause depression of bone marrow with anemia, leukopenia and thrombocytopenia. Thiourea was used in former times as a thyroid depressant in patients with hyperthyroidism. A daily dose of <15 mg (<0.2 mg/kg body weight per day for a 70-kg adult) in adults did not lead to measurable depression of the thyroid gland function, while a dose of 70 mg/day (about 1.0 mg/kg body weight per day) produced a remission of hyperthyroidism. ANIMAL STUDIES: Thiourea is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals. When administered in the drinking water, thiourea induced thyroid adenomas and carcinomas in rats of both sexes and squamous cell carcinomas of the Zymbal gland in male rats. When administered in the diet, thiourea induced hepatocellular adenomas in rats and hepatomas in rainbow trout. When injected intraperitoneally and administered in drinking water, thiourea induced squamous cell carcinomas and mixed cell sarcomas in the Zymbal gland of rats of both sexes. Thiourea also causes development and reproductive abnormalities. In studies with pregnant ewes administered 50 mg thiourea/kg body weight daily for 2, 4, or 6 months, abortion, stillbirth, birth of weak/low-weight lambs, dystokia, and retention of placenta were common features. The severity of changes was dependent upon the stage of gestation when hypothyroidism was induced. High dose thiourea severely inhibited thyroid function in rat pups, significantly depressed body growth, and retarded development of the acoustic startle response. At the low dose there was a significant reduction in growth, but no effect on acquisition of acoustic startle reflex. Thiourea has shown genotoxicity. When tested at a dose range of 1X10-2 to 1X10-5 M, was found to be weakly active in causing unscheduled DNA synthesis. In hepatocytes, thiourea elicited a linear increase in DNA repair replication in the concentration range tested (5-25 mM). In V79 cells, thiourea (10-40 mM) significantly increased the frequency of 8-azaguanine-resistant mutants. ECOTOXICITY: Treatment with 0.03% thiourea via immersion for 21 days induced hypothyroidism (thyroid hormone depletion) as evidenced by significantly reduced serum T(3) levels in the catfish, Clarias gariepinus. Thiourea-treated males had narrowed seminiferous lobules with fewer spermatozoa in testis, very little or no secretory fluid, reduced protein and sialic acid levels in seminal vesicles when compared to controls; accompanied by reduction in serum and tissue levels of testosterone (T) and 11-ketotestosterone (11-KT), a potent male specific androgen in fish. There were physiological and histological signs of recovery after 21 days such as reappearance of spermatozoa and partial restoration of 11-KT and T levels. In yearling rainbow trout, Salmo gairdneri, thiourea treatment resulted in depression of gill Na+/K+-ATPase activity in sea water (in 0.5% thiourea) or delayed adaptive increase in ATPase activity (in 0.3% thiourea) following sea water entry as compared to control fish.

/AQUATIC SPECIES/ /Thiourea-induced thyroid hormone depletion /was used/ ... to understand the influence of thyroid hormones on testicular recrudescence of the air-breathing catfish, Clarias gariepinus. Treatment with 0.03% thiourea via immersion for 21 days induced hypothyroidism (thyroid hormone depletion) as evidenced by significantly reduced serum T(3) levels. Thiourea-treated males had narrowed seminiferous lobules with fewer spermatozoa in testis, very little or no secretory fluid, reduced protein and sialic acid levels in seminal vesicles when compared to controls. The histological changes were accompanied by reduction in serum and tissue levels of testosterone (T) and 11-ketotestosterone (11-KT), a potent male specific androgen in fish. Qualitative changes in the localization of catfish gonadotropin-releasing hormone (cfGnRH) and luteinizing hormone (LH, heterologous system) revealed a reduction in the distribution of immunoreactive neuronal cells and fibers in thyroid depleted fish. Interestingly, thiourea-withdrawal group showed physiological and histological signs of recovery after 21 days such as reappearance of spermatozoa and partial restoration of 11-KT and T levels. These data demonstrate that thyroid hormones play a significant role in testicular function of catfish. The mechanism of action includes modulating sex steroids either directly or through the hypothalamo (GnRH)-hypophyseal (LH) axis.

/AQUATIC SPECIES/ Exposure of yearling rainbow trout, /Oncorhynchus mykiss/, to either 0.3% or 0.5% thiourea in fresh water or subsequently in dilute sea water; impaired osmoregulatory performance in both media. Thiourea treatment resulted in depression of gill Na+/K+-ATPase activtiy in sea water (in 0.5% thiourea) or delayed adaptive increase in ATPase actvity (in 0.3% thiourea) following sea water entry as compared to control fish. Plasma Na+ and Cl- levels decreased in fresh water fish and increased in sea water acclimated fish exposed to thiourea. T4 replacement did not abolish these effects. Neither did thiourea treatment depress circulating levels of total T4, and the observed effects were probably associated with thiourea toxicity in extrathyroidal sites. The effectiveness of thiourea to block thyroid function in fish is discussed.

/AQUATIC SPECIES/ Methylmercury (CH3Hg(II)) was measured in various tissues and whole body of sheepshead minnows, Cyprinodon variegatus, following exposure to 100 ng/L methylmercury chloride (CH3HgCl) alone or in combination with one of the organic compounds cysteine (CH3Hg-Cys), thiourea (CH3Hg-Thu), or thioglycolate (CH3Hg-Thg). Overall, the CH3Hg(II) concentration in sheepshead minnows in all the treatments increased with time and was significantly different from the unspiked controls after 24 hr. Addition of the organic compounds increased the bioavailability of CH3Hg(II) in the whole body of the fish after 72 hr. In particular, the CH3Hg(II) concentration after CH3Hg-Thg and CH3Hg-Thu exposure was, respectively, approximately 1.3- and 1.6- fold higher than with CH3HgCl exposure. A composite of the CH3Hg(II) concentrations in the visceral organs (gill, liver, and intestine) highlighted the effect of the organic compounds, where concentrations in all mercury-thiolate treatments were significantly higher than CH3HgCl alone after 72 hr. The most dramatic changes in the different tissues measured were observed in the liver, where the CH3Hg(II) concentrations in the sulfur treatments were significantly higher than the CH3HgCl treatment after 72 hr. The results of this study suggest that the CH3Hg-thiolate complexes were bioavailable to sheepshead minnows and effectively induced CH3Hg(II) uptake in tissues at environmentally realistic CH3HgCl concentrations.

Cough.

Redness.

EPA has released the first beta version (version 0.5) of the Interactive Chemical Safety for Sustainability (iCSS) Dashboard. The beta version of the iCSS Dashboard provides an interactive tool to explore rapid, automated (or in vitro high-throughput) chemical screening data generated by the Toxicity Forecaster (ToxCast) project and the federal Toxicity Testing in the 21st century (Tox21) collaboration. /The title compound was tested by ToxCast and/or Tox21 assays; Click on the "Chemical Explorer" button on the tool bar to see the data./[USEPA; ICSS Dashboard Application; Available from, as of December 8, 2014: http://actor.epa.gov/dashboard/]

Substances generally prohibited from direct additiion or use as human food. a) Thiourea is the chemical thiocarbamide, CH4N2S. It is a synthetic chemical, is not found in natural products at levels detectable by the official methodology, and has been proposed as an antimycotic for use in dipping citrus. (b) Food containing any added or detectable level of thiourea is deemed to be adulterated under the act.

U219; As stipulated in 40 CFR 261.33, when thiourea, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to Federal and/or State hazardous waste regulations. Also defined as a hazardous waste is any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5).

Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329. Effective date 9/29/2006; Reporting date: 11/28/2006.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Thiourea is included on this list. Effective date 9/29/2006; Sunset date: 11/28/2006.

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 10 lb or 4.54 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).

Used in compounds to clean silver and copper; also used in diazo copy paper; [Kanerva, p. 1839] Used in photography (toning solution); [www.ci.tucson.az.us/arthazards/medium.html]

Working with Glues and Adhesives [Category: Other]

For thiourea (USEPA/OPP Pesticide Code: 080201) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Thiourea is used in four main ways: as an intermediate in the production of thiourea dioxide for wool and textile processing (30%), in ore leaching (25%), in diazo papers (15%) and as a catalyst in fumaric acid synthesis (10%); the remainder has smaller areas of use.

Thiourea has a wide range of uses, e.g., for producing and modifying textile and dyeing auxiliaries, in the production and modification of synthetic resins, in repro technology, in the production of pharmaceuticals (sulfathiazoles, tetramisole, and cephalosporins), in the production of industrial cleaning agents (e.g., for photographic tanks and metal surfaces in general), for engraving metal surfaces, as an isomerization catalyst in the conversion of maleic to fumaric acid, in copper refining electrolysis, in electroplating (e.g., of copper), and as an antioxidant (e.g., in biochemistry). Other uses are as an additive for slurry explosives, as a viscosity stabilizer for polymer solutions (e.g., in drilling muds), and as a mobility buffer in petroleum extraction. The removal of mercury from wastewater from chlorine-alkali electrolysis and gold and silver extraction from minerals are also of economic importance.

Thiourea use in thyrotoxicosis is discontinued.

2023: 4,864,278 lb

(1991) Exceeded 5000 lb or US $5000 in value

Thiourea is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

Production volumes for non-confidential chemicals reported under the Inventory Update Rule.[Table#3123]

Production volume for non-confidential chemicals reported under the 2006 Inventory Update Rule. Chemical: Thiourea. Aggregated National Production Volume: 500,000 to < 1 million pounds.

Non-confidential 2012 Chemical Data Reporting (CDR) information on the production and use of chemicals manufactured or imported into the United States. Chemical: Thiourea. National Production Volume: 1,000,000 - 10,000,000 lb/yr.

Production of thiourea is now carried out by treating technical-grade calcium cyanamide (CaCN2) with hydrogen sulfide or one of its precursors, e.g., ammonium sulfide or calcium hydrogen sulfide [19]. The calcium cyanamide must contain at least 23% nitrogen and must be free from calcium carbide (CaC2), as otherwise explosive acetylene is liberated by water or hydrogen sulfide. ... A reaction vessel is charged continuously with an aqueous suspension of calcium cyanamide and a mixture of hydrogen sulfide and carbon dioxide, such that the above reactions go to completion. The converted reaction mixture is removed continuously from the reactor and excess H2S is removed by stripping. Waste-gas from the reactor contains hydrogen sulfide, which is purified in a scrubber connected to the reactor. The stripped thiourea solution is filtered to remove the precipitated calcium carbonate formed as one of the reaction products. The filtrate is evaporated in vacuum and thiourea is crystallized by cooling. It is filtered, washed, and dried in an air stream.

Made by fusing ammonium thiocyanate: R. E. Powers, United States of America patent 2552584; R. E. Powers, J. Mitchell, United States of America patent 2560596 (both 1951 to Koppers); by treating cyanamide with hydrogen sulfide: R. O. Roblin, Jr., United States of America patent 2173067 (1940 to American Cyanamid); W. F. Lewis, United States of America patent 2393917 (1946 to Monsanto); J. van de Kamp, United States of America patent 2357149 (1944 to Merck & Co.).

(1) By heating dry ammonium thiocyanate, extraction with a concentrated solution of ammonium thiocyanate, with subsequent crystallization; (2) action of hydrogen sulfide on cyanamide.

Thiourea is available in the USA as a lab chemical containing 99% active ingredient. The specifications for a West German commercial product were as follows: 99% minimum active ingredient, 0.15% maximum water, 0.1% maximum ash, 0.4% maximum dicyanodiamide and traces of sulfate ion.

Thiourea is commercially available in Germany with the following typical specifications: purity, greater than or equal to 99.0%; water, less than or equal to 0.30%; ash, less than or equal to 0.10%; thiocyanate (rhodanide), less than or equal to 0.15%; other nitrogen-containing compounds, less than or equal to 0.5%; and iron, less than or equal to 10 mg/kg.

Grades: Technical, reagent.

Not Known or Reasonably Ascertainable

Thiourea: ACTIVE

Each year, an estimated 35,000 wells are hydraulically-fractured in the U.S. Although the oil and gas extraction industry as a whole has a relatively higher fatality rate compared to most of the U.S. general industry... there is currently no worker injury/illness or fatality data publicly available for hydraulic fracturing or flowback operations. Regardless of the availability of data, more workers are potentially exposed to the hazards created by hydraulic fracturing and flowback operations due to the large increase in the number of these operations in the past decade. /Hydraulic fracturing/