4,4'-Methylenebis(2-chloroaniline) is a synthetic chemical that occurs as tan coloured pellets or flakes. It has a faint amine odour, very low solubility in water, and may explode when heated. It is generally referred to as MOCA, but may also be called bisamine, MBOCA, or MCA. There are numerous other synonyms and product names; see Hazardous Substances Data Bank (HSDB) for more information.
MOCA has been classified by the International Agency for Research on Cancer (IARC) as Group 1, a known human carcinogen. It was first classified as a Group 2A carcinogen in 1987, but was re-classified as Group 1 in 2008 based on strong genotoxic mechanistic evidence. MOCA's Group 1 classification was reaffirmed under IARC's review of Group 1 carcinogens in 2012. In experimental animals, MOCA causes liver, bladder, and lung cancer.
Additionally, when MOCA is inhaled or ingested it can cause cyanosis (blue coloration of lips, fingernails or skin), as well as confusion, dizziness, headache, nausea, abdominal pain, unconsciousness, and convulsions. Chronic exposure can also cause blood disorders.
stel = short term exposure limit (15 min. maximum)
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value (8 hour maximum)
Canadian Environmental Guidelines
Ontario Ambient Air Quality Objective
24 hour: 10 μg/m3
BC's Contaminated Sites Regulation, BC Reg 375
Sets soil standards for:
Agricultural, urban park, and residential soil: 37 μg/g
Commercial and industrial soil: 130 μg/g
Drinking water standard: 5.2 μg/L
μg/m3 = micrograms per cubic metre
μg/g = micrograms per gram
μg/L = micrograms per liter
MOCA was not included in other Canadian environmental guidelines reviewed .[10,11,12,13,14,15,16]
DSL – high priority substance with intermediate potential for exposure
Agreement Respecting the Great Lakes Basin Ecosystem
Listed as a "Hazardous Polluting Substance"
DSL = domestic substances list
MOCA was not included in other Canadian government chemical listings reviewed[19,20,21]
MOCA is primarily used as a curing agent for polyurethane elastomers and epoxy resins. It has been used in research laboratories as a model compound for studying carcinogens.[2,7]
As of 2005 in Canada, MOCA was primarily used as a curing agent for polyurethane prepolymers. These prepolymers were used to make specialized, castable polyurethane products such as industrial tires and rollers, shock absorption pads, conveyor belting, sport boots, roller skate wheels, cameras, computers, electrical components and wear-resistant industrial products. Newer information on Canadian uses was not found.
Canadian Production and Trade
Polyurethane products and epoxy resins are manufactured in Canada;[23,24,25,26] given that MOCA is used in conjunction with these processes, it is likely used in Canada. Companies such as Polymark Manufacturing, ACR Group, and Elastochem Specialty Chemicals manufacture polyurethane products in Canada.[24,26]
MOCA was not being produced in Canada in 2000, and new evidence for its production was not found. In the same year, Canada imported 100 to 1000 tonnes of MOCA.
No export or import data on MOCA was included in the TradeMap database.
The most important route of occupational exposure to MOCA is dermal absorption, followed by inhalation and ingestion.
The main occupations exposed to MOCA include workers involved in its manufacture and in producing polyurethane and epoxy where MOCA is used as a curing agent.[2,7] MOCA has been detected on a number of workplace surfaces in MOCA and polyurethane production plants, which suggests potential dermal exposure for workers.[7,28] In a polyurethane factory, MOCA was detected in the air in areas where it was melted and used, indicating that chemical mixers and moulders would have the highest inhalation exposure to MOCA.
CAREX Canada has not prioritized MOCA for exposure estimate development. This is because there is a lack of exposure monitoring data in the Canadian Workplace Exposure Database on which to base an estimate.
MOCA is not a naturally-occurring chemical, so any found in the environment is from industrial releases or spills.[22,28] Sources of environmental exposure include dermal exposure to contaminated soil and ingesting root vegetables grown in contaminated soil.
Once released, MOCA will strongly adsorb to organic matter in soil or in sediment. Because of its low solubility in water, contamination of groundwater and surface water is unlikely.[4,28]
Para-occupational exposures may occur in family members of workers exposed to MOCA.
Trace amounts of unreacted MOCA may be present in some plastic products, however because MOCA has a high molecular weight and low volatility, exposure in consumers is expected to be very low.
No household products are listed as containing MOCA in the Household Products Database from the United States.
A search of Environment Canada's National Pollutant Release Inventory (NPRI) database yielded the following results on current potential for exposure to MOCA in Canada:
Our team has performed a detailed scan of exposure control resources and assembled a compilation of key publications and resources. These are organized by type of exposure (environmental or occupational) and by specificity (general or carcinogen-specific). Please visit our Exposures Reduction Resources page to view.
We also recommend exploring the Prevention Policies Directory, a freely-accessible online tool offering information on policies related to cancer and chronic disease prevention. Providing summaries of the policies and direct access to the policy documents, the Directory allows users to search by carcinogen, risk factor, jurisdiction, geographical location, and document type. Click here to learn more about policies specific to MOCA in the Directory. For questions about this resource, please contact a member of the Prevention Team at the Canadian Partnership Against Cancer at firstname.lastname@example.org.