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Formaldehyde

DESIGNATIONS

CAS No.: 50-00-0
Registry names: Formaldehyde
Chemical name: Methanal
Synonyms, Trade names:
Formic acid aldehyde, formalin, methyl aldehyde, oxomethane, methyleneoxide, oxymethylene, formyl hydrate, Formol, Fannoform, BFV, Formalith, Ivalon, Lysoform, Morbicid, Superslysoform, Tannosynt, Antverruc, Sandovac, Vobaderin
Chemical name (German):
Formaldehyd, Methanal
Chemical name (French):
Formaldhyde, Mthanal
Appearance: colourless gas with pungent odour

Note: Commercially available aqueous solutions contain 35-55% formaldehyde. As formaldehyde has a tendency towards polymerisation, these solutions are stabilised with methanol (The addition of methanol increases the flammability).

BASIC CHEMICAL AND PHYSICAL DATA

Empirical formula: CH2O
Rel. molecular mass: 30.03 g
Density: 0.8153 g/cm3 (liquid at -20C)
Relative gas density: 1.04
Boiling point: -19.2C (pure substance)
Melting point: -92.0 to -118.0C
Flash point: 32-61C (aqueous solution)
Ignition temperature: 300-430C (aqueous solution)
Explosion limits: 7-73 % by vol.
Solvolysis/solubility: in water: completely soluble

readily soluble in ether, alcohol and other polar solvents

Conversion factors: 1 mg/m3 = 0.80 ppm

1 ppm = 1.25 mg/m3

ORIGIN AND USE

Usage:
The use of formaldehyde is extremely widespread and dependent on the additives (e.g. urea, melanin, phenol, ammonia). It is thus used in differing concentrations in adhesives (e.g. for the production of chipboard), foams, tanning agents, explosives, dyes, preserving agents, solvents, pharmaceuticals, resins and fungicides.

Origin/derivation:
Formaldehyde is produced by oxidising methanol using silver or metal oxide catalyst methods (iron and molybdenum). In addition to the emissions resulting from the production and its usage, formaldehyde is released into the atmosphere due to incomplete combustion and the photochemical degradation of organic trace substances.

Production figures:
The production figures in Germany between 1980 and 1982 were about 500,000 tons (BMFJG, 1984). In 1978, 2.9 million tons were produced in the USA. Japan produced 1.2 million tons of formaldehyde in 1979 (WHO, 1982).

Toxicity

Humans: LDLo female 36 mg/kg, oral acc. UBA, 1986
TCLo 17 mg/m3 (30 min), inhalation acc. UBA, 1986
TCLo 8 ppm, inhalation acc. UBA, 1986
LDLo 477 mg/kg (unreported) acc. UBA, 1986
Mammals:
Mouse: LC50 300 mg/m3, subcutaneous acc. WHO, 1982
Rat: LD50 800 mg/kg, oral acc. WHO, 1982
Rat: LC50 590 mg/m3, inhalation acc. WHO, 1982
Rat: LD50 87 mg/kg, intravenous acc. WHO, 1982
Rabbit: LD50 270 mg/kg, dermal acc. WHO, 1982
Guinea pig: LD50 260 mg/kg, oral acc. WHO, 1982
Aquatic organisms:
Small crustaceans: LC0 27 mg/l acc. UBA, 1986
Small crustaceans: LC50 52 mg/l acc. UBA, 1986
Small crustaceans: LC100 77 mg/l acc. UBA, 1986
Fish: LC100 28.4 mg/l acc. UBA, 1986
Algae: LC50 0.3-0.5 mg/l acc. UBA, 1986
Water flea: LC50 2 mg/l acc. UBA, 1986

Characteristic effects:

Humans/mammals: Formaldehyde causes major irritation of the mucous membranes, the conjunctiva, the skin and the upper part of the respiratory tract both as a gas and as vapour or aerosol. In aqueous solutions, it is a protoplasmic poison with caustic and protein-denaturating effect. Skin contact produces surface coagulation, necroses with hardening, tanning and anaesthetisation. Swallowing or inhaling large quantities causes burning of the oesophagus or the trachea, pains in the gastro-intestinal tract, nausea, loss of consciousness and collapse. 60 ml of liquid or 650 ml of vapour per m3 are potentially lethal after a few minutes. The carcinogenic potential is a case for intense scientific discussion likely to be affirmed. Delayed and cumulative damage has not yet been established.

ENVIRONMENTAL BEHAVIOUR

Water:
Because of its good solubility, some 99% of the formaldehyde which is released into the environment is found in water (BMFJG, 1984).

Air:
Approximately 1% of the formaldehyde emitted into the environment reaches the atmosphere, but it is readily washed out again by precipitation. There is no long-distance transportation due to the relatively short half-life. Pressurised formaldehyde forms a cold mist when depressurised. This mist is denser than air, vaporises easily and forms aggressive and explosive mixtures with air (including over the water surface).

Soil:
The effects of the substance in soil are unknown, however no bioaccumulation has been established to date. Infiltration into the groundwater is of minor concern because of the tendency of formaldehyde to evaporate from soil.

Half-life:
The half-life in air (urban air with sun rays) is between 1 and 2 hours, or 12 hours if hydroxo radicals are present.

Degradation, decomposition products:
Degradation is performed by microorganisms in soil and water. At temperatures above 150C, formaldehyde decomposes to form methanol and carbon monoxide. There is little stability under atmospheric conditions as a result of the short half-life (BMFJG, 1984). Formaldehyde is subject to spontaneous polymerisation in contact with acids and alkalis. It reacts with water to form polymethylenes. When exposed to HCl, formaldehyde forms the highly carcinogenic bis(chloromethyl)ether and catalyzes secondary amines to form carcinogenic nitrosamines/N-nitroso compounds.

Food chain:
There is only slight accumulation in the food chain. Formaldehyde is rapidly oxidised in the organism to formic acid, which is partly excreted with urine.

Combination effects:
Formaldehyde enters into vigorous condensation reactions with ammonia or amines and is disproportionated with alkalis to form methanol and formic acid.

ENVIRONMENTAL STANDARDS

Medium/ acceptor Sector Country/ organ.

Status

Value Cat. Remarks Source
Air: Emiss. D L 20 mg/m3   mass flow > 0.1 g/h acc. TA Luft, 1986
  DDR

(L)

0.012 mg/m3   Long-time value acc. HORN, 1989
  DDR

(L)

0.035 mg/m3   Short-time value acc. HORN, 1989
  WHO

G

100 g/m3   24 h acc. UBA, 1988
  D

L

0.03 mg/m3 MIK Long-time value DFG, 1988
  D

L

0.07 mg/m3 MIK Short-time value DFG, 1988
Workp AUS

L

3 mg/m3     acc. WHO, 1982
Workp B

G

3 mg/m3     acc. WHO, 1982
Workp BG

G

1 mg/m3   1) acc. BMFJG, 1984
Workp CS

G

2 mg/m3     acc. WHO, 1982
Workp CS

G

5 mg/m3   10 min acc. WHO, 1982
Workp D

L

0.6 mg/m3 MAK   DFG, 1989
Workp D

G

0.123 mg/m3   2) acc. WHO, 1982
Workp DDR

(L)

0.5 mg/m3   Short-time value acc. HORN, 1989
Workp DK

(L)

0.148 mg/m3   2) acc. WHO, 1982
Workp H

(L)

1 mg/m3     acc. WHO, 1982
Workp I

(L)

1.2 mg/m3   Long-time value acc. WHO, 1982
Workp I

(L)

0.12 mg/m3     acc. BMFJG, 1984
Workp J

(L)

2.5 mg/m3     acc. WHO, 1982
Workp NL

L

1.2 mg/m3     acc. BMFJG, 1984
Workp NL

G

0.12 mg/m3   2) acc. BMFJG, 1984
Workp PL

G

2 mg/m3     acc. WHO, 1982
Workp RO

G

4 mg/m3   3) acc. WHO, 1982
Workp S

(L)

3 mg/m3   10 min3) acc. WHO, 1982
Workp S

(L)

0.6 mg/m3   4) acc. BMFJG, 1984
Workp S

(L)

0.12 - 0.5 mg/m3     acc. BMFJG, 1984
Workp S

G

0.123 mg/m3   2) acc. WHO, 1982
Workp SF

(L)

1.2 mg/m3     acc. BMFJG, 1984
Workp SF

G

3 mg/m3     acc. WHO, 1982
Workp SU

(L)

0.5 mg/m3 PDK 3) acc. SORBE, 1988
Workp USA

(L)

1.5 mg/m3 TWA   acc. SORBE, 1988
Workp USA

(L)

3 mg/m3 STEL 30 min acc. WHO, 1982
Workp USA

(L)

0.13 mg/m3     acc. BMFJG, 1984
Workp USA

(L)

0.6 mg/m3   5) acc. BMFJG, 1984
Workp YU

(L)

1 mg/m3     acc. WHO, 1982

Further legislation:

- The concentration levels in chipboard in the Federal Republic of Germany must not exceed the following (ETB, 1980): Emission class 1 (E1) max. 0.1 ppm; emission class 2 (E2) max. 1 ppm; emission class 3 (E3) max. 2.3 ppm. There are no regulations to date regarding the use of chipboard in furniture and in the Do-it-yourself sector.

- There are similar regulations in Belgium and Japan (chipboard classification).

- The maximum concentration levels in the Federal Republic of Germany for finished products are as follows for cosmetics (Order Governing Cosmetics, 1977): nail hardeners: 5%; preservative agent: 0.2%; mouthwash 0.1%

- The quality requirements imposed on urea-resin in-situ foams used for insulation are regulated in the Federal Republic of Germany by DIN Standard 18159.

- There is a total ban on UF foam insulation in Canada.

- The Japanese likewise control the concentration in wallpapers and adhesives and there is a ban on formaldehyde as an additive in the treatment and packaging of foodstuffs as well as in paints. The substance is limited to 75 ppm in textiles (BMJFG, 1984).

Notes:

1) For stationary systems
2) Indoor air
3) Maximum value
4) For new systems
5) Minnesota

Comparison/reference values

Medium/origin Country Value Source
Air:
Los Angeles, California (1961-66): USA 0.005-0.16 mg/m3 acc. BMJFG, 1984
Road air (1977) CH 0.0011-0.0012 mg/m3 acc. BMJFG, 1984
Sea air (1979) D 0.00012-0.008 mg/m3 acc. BMJFG, 1984
Automobile emissions   35.7-52.9 mg/m3 acc. BMJFG, 1984
Interior of house (1975): DK 0.08-2.24 mg/m3 acc. BMJFG, 1984
Indoor air (BMJFG, 1984; Tests between 1975 and 1984):
Chipboard:      
New schools   0.36-1.08 mg/m3 (little exchange of air)  
Classrooms and homes   0.6-0.72 mg/m3 (furniture)  
Prefabricated house   0.18-1.08 mg/m3  
Houses in USA   0.012-3.84 mg/m3 (636 houses)  
Thermal insulation   0.24-3.48 mg/m3 (43 properties)  
Disinfection:      
Pathology   < 13.56 mg/m3 (following removal)  
Bed disinfection   < 6 mg/m3  
Disinfection by scrubbing   < 13.2 mg/m3  
Spray disinfection   < 12 mg/m3  
Incubator air   18-30 mg/m3  
Rainwater:
Mainz (1974-1977) D 0.174 0.085 g/l acc. BMJFG, 1984
Deuselbach (1974-1976) D 0.141 0.048 g/l acc. BMJFG, 1984
Clean-air zone (1977) IRL 0.111 0.059 g/l acc. BMJFG, 1984
Foodstuffs and semi-luxury goods:
Tomatoes   5.7-7.3 g/kg acc. WHO, 1982
Apples   17.3-22.3 g/kg acc. WHO, 1982
Spinach   3.3-7.3 g/kg acc. WHO, 1982
Carrots   6.7-10 g/kg acc. WHO, 1982
Radish   3.7-4.4 g/kg acc. WHO, 1982
Cigarette smoke   37.5-44.5 g/cigarette acc. WHO, 1982

Assessment/comments

Workplace exposure is not the only way by which formaldehyde enters the human body. Its use as an adhesive in the manufacture of chipboard and its mixing with urea for in-situ foams is controlled both in Germany and in several other countries. When the above building materials are used, formaldehyde degases into the air inside residential buildings. The carcinogenic potential of formaldehyde has yet to be reliably established. Isolated animal experiments point to the possibility of a carcinogenic and teratogenic effect.

Special sources: BMFJG (1984)


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