Dimethylacetamide (DMA or DMAc), also known as acetic acid-dimethylamide, N,N-dimethylacetamide or acetyldimethylamine, is an organic compound with the formula CH3C(O)N(CH3)2.[fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”]It is a colourless (to yellow), water miscible, oily, polar, hygroscopic liquid with a faint, specific amine-like odour. DMAc is miscible with most other organic solvents including alcohols, ethers, esters ketones, chlorinated and aromatic compounds, although it is poorly soluble in saturated aliphatic hydrocarbons. It has a good thermal and chemical stability. 
Dimethylacetamide is used for many organic reactions and industrial applications. It can be a reactor solvent or plasticiser for cosmetic and pharmaceuticals, an extraction agent for gases and oils. It can be applied as a solvent for the manufacture of films, acrylic fibres, X-ray contrast media, polyimide resins, polysulfones and cellophane.
Sources & Routes of Exposure [3,4]
Dimethylacetamide is used in industrial settings only. The possible routes of potential exposure for workers are inhalation, contact with the skin/eyes and ingestion. Dimethylacetamide may enter the body through the skin.
Acute Health Effects Ingestion
§ Swallowing of the liquid may cause aspiration into the lungs with the risk of chemical pneumonitis; serious consequences may result.
§ When N,N-dimethylacetamide (DMAc) given to humans in daily doses (400 mg/kg for 3 days), depression, lethargy, confusion and disorientation ensued. In some patients there were visual and auditory hallucinations, perceptual distortions, delusions, emotional detachment and effective blunting, all reminiscent of the reactions induced by mescaline and by lysergic acid derivatives.§ Considered an unlikely route of entry in commercial/industrial environments.
§ The liquid may produce gastrointestinal discomfort and may be harmful if swallowed.
§ Evidence exists, or practical experience predicts, that the material may cause eye irritation in a substantial number of individuals.
§ Prolonged eye contact may cause inflammation characterised by a temporary redness of the conjunctiva (similar to windburn).
§ Skin contact with the material may be harmful; systemic effects may result following absorption.
§ The material is not thought to be a skin irritant (as classified using animal models). Temporary discomfort, however, may result from prolonged dermal exposures.
§ Open cuts, abraded or irritated skin should not be exposed to this material.
§ Entry into the blood-stream through, for example, cuts, abrasions or lesions, may produce systemic injury with harmful effects. Examine the skin prior to the use of the material and ensure that any external damage is suitably protected. Inhalation
§ Inhalation of vapours or aerosols (mists, fumes), generated by the material during the course of normal handling, may be harmful.
§ The material is not thought to produce respiratory irritation (as classified using animal models). Nevertheless inhalation of vapours, fumes or aerosols, especially for prolonged periods, may produce respiratory discomfort and occasionally, distress.
§ Inhalation of N,N-dimethylacetamide (DMAc) may cause headache, nausea, vomiting, intolerance to alcohol, abdominal spasm and diarrhoea. Large doses can result in depression, lethargy, disorientation, and visual and auditory hallucinations.
Chronic Health Effects Ample evidence exists, from results in experimentation, that developmental disorders are directly caused by human exposure to the material. Limited evidence suggests that repeated or long-term occupational exposure may produce cumulative health effects involving organs or biochemical systems. Repeated exposure of 20 to 25 ppm N,N-dimethylacetamide (DMAc) (due to appreciable skin absorption) has caused jaundice in workers; evidence of liver damage and hepatic dysfunction is clear. Workers exposed to DMAc for 2-10 years showed abnormal liver function. Chronic exposure can result in cumulative liver and kidney damage. (Repeated dermal application of the liquid to dogs caused severe fatty infiltration of the liver; repeated exposure of rats to the vapour resulted in focal necrosis of the liver.) Teratogenic effects from dermal application were reported in rats when DMAc was applied on gestation days 10 and 11 at a total does of 2400 mg/kg body weight. When DMAc was administered to rats by gavage at a dosage of 400 mg/kg/day on days 6 through 19 of gestation, malformations of the heart, major blood vessels and oral cavity were seen. Maternal toxicity and post-implantation loss were also seen at this dose. Some evidence exists that a demethylation metabolite, acetamide, is a rat liver carcinogen.
First Aid Measures
§ Ingestion: If swallowed do NOT induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain open airway and prevent aspiration. If spontaneous vomiting appears imminent or occurs, hold patient’s head down, lower than their hips to help avoid possible aspiration of vomitus.
§ Eye contact: Wash out immediately with fresh running water. Ensure complete irrigation of the eye by keeping eyelids apart and away from eye and moving the eyelids by occasionally lifting the upper and lower lids.
§ Skin contact: Immediately remove all contaminated clothing, including footwear. Flush skin and hair with running water (and soap if available).
§ Inhalation: If fumes or combustion products are inhaled remove from contaminated area. Lay patient down. Keep warm and rested.
§ Note to physician: Any material aspirated during vomiting may produce lung injury. Therefore emesis should not be induced mechanically or pharmacologically. Treat symptomatically for poisons (where specific treatment regime is absent).
Exposure Controls & Personal Protection
§ Engineering controls are the most effective way of reducing exposure. The best protection is to enclose operations and/or provide local exhaust ventilation at the site of chemical release. Isolating operations can also reduce exposure. Using respirators or protective equipment is less effective than the controls mentioned above, but is sometimes necessary. Special controls should be in place for highly toxic chemicals or when significant skin, eye, or breathing exposures are possible. In addition, the following control is recommended: Where possible, automatically pump liquid dimethylacetamide from drums or other storage containers to process containers.
§ Good work practices can help to reduce hazardous exposures. The following work practices are recommended: Workers whose clothing has been contaminated by dimethylacetamide should change into clean clothing promptly. Contaminated work clothes should be laundered by individuals who have been informed of the hazards of exposure to dimethylacetamide. Eye wash fountains should be provided in the immediate work area for emergency use. If there is the possibility of skin exposure, emergency shower facilities should be provided. At the end of the workshift, wash any areas of the body that may have contacted dimethylacetamide, whether or not known skin contact has occurred. Do not eat, smoke, or drink where dimethylacetamide is handled, processed, or stored, since the chemical can be swallowed. Wash hands carefully before eating, drinking, smoking, or using the toilet.
Personal Protective Equipment The following personal protective equipment is recommended when handling dimethylacetamide:
§ Clothing: Wear solvent-resistant gloves and clothing. Safety equipment suppliers/manufacturers can provide recommendations on the most protective glove/clothing material for your operation.
§ All protective clothing (suits, gloves, footwear, headgear) should be clean, available each day, and put on before work.
§ Safety equipment manufacturers recommend- Butyl Rubber as a protective material.
§ Eye Protection: Wear indirect-vent, impact and splash resistant goggles when working with liquids. Wear a face shield along with goggles when working with corrosive, highly irritating or toxic substances. Contact lenses should not be worn when working with this substance.
§ Respiratory Protection: Such equipment should only be used if the employer has a written program that takes into account workplace conditions, requirements for worker training, respirator fit testing and medical exams, as described in OSHA 1910.134. Where the potential exists for exposure over 10 ppm, use a MSHA/NIOSH approved supplied-air respirator with a full facepiece operated in a pressure-demand or other positive-pressure mode. For increased protection use in combination with an auxiliary self-contained breathing apparatus operated in a pressure-demand or other positive-pressure mode. Exposure to 300 ppm is immediately dangerous to life and health. If the possibility of exposure above 300 ppm exists, use a MSHA/NIOSH approved self-contained breathing apparatus with a full facepiece operated in a pressure-demand or other positive-pressure mode.
OSHA: The Occupational Safety & Health Administration has set the following Permissible Exposure Limits (PEL) for dimethylacetamide:
- General Industry: 29 CFR 1910.1000 Z-1 Table — 10 ppm, 35 mg/m3 TWA; Skin
- Construction Industry: 29 CFR 1926.55 Appendix A — 10 ppm, 35 mg/m3 TWA; Skin
- Maritime: 29 CFR 1915.1000 Table Z-Shipyards — 10 ppm, 35 mg/m3 TWA; Skin
ACGIH: The American Conference of Governmental Industrial Hygienists has established a Threshold Limit Value (TLV) for dimethylacetamide of10 ppm, 36 mg/m3 TWA; Skin; Appendix A4 – Not Classifiable as a Human Carcinogen; BEI (TLV listed under N,N-Dimethylacetamide)
NIOSH: The National Institute for Occupational Safety and Health has set a Recommended Exposure Limit (REL) for dimethylacetamide of 10 ppm, 35 mg/m3 TWA; Skin