Download What are the long-term health effects of exposure to

What are the main health hazards associated
with breathing in formaldehyde solutions?
Formaldehyde solutions can release formaldehyde gas, which is extremely
irritating and very toxic if inhaled, posing a very serious inhalation hazard.
The amount of gas released depends on the concentration of formaldehyde
and other ingredients present in the formulation.
The odour of formaldehyde gas can be recognized at concentrations as low as
0.03-1.9 ppm. It causes mild to moderate irritation of the nose and throat at
0.3-3 ppm. Up to 20% of the population are more responsive and may react
acutely to formaldehyde at very low concentrations (0.25 ppm). Exposure to
10 ppm causes severe irritation of the upper respiratory tract, with a burning
sensation of the nose and throat. Other effects include coughing, choking and
vomiting. Exposure to 50 ppm or higher may lead to inflammation of the lung
(pneumonitis) or to a potentially fatal accumulation of fluid in the lungs
(pulmonary edema). Symptoms of pulmonary edema (chest pain and
shortness of breath) can be delayed for up to 24 or 48 hours after exposure.
In a study of funeral home employees, exposure to 0.25-1.77 ppm
formaldehyde produced nose irritation, sneezing, coughing, and headaches in
an unspecified number of embalmers. Thirty-three volunteers exposed to 0,
0.25, 0.5, 1 or 2 ppm formaldehyde (generated from heating
paraformaldehyde) for 90 minutes experienced irritation of the nose and
throat at all concentrations, with severity increasing with concentration. In a
study of 23 students exposed to 0.02-2.7 ppm (cited as 0.02-3.3 mg/m3) and
phenol from cadavers, most experienced nose and throat irritation,
headache, dizziness, and cough. Of 12 who had post-exposure testing, one
showed a significant decrease in pulmonary function. The effects were
attributed to the formaldehyde exposure.
No case reports of death from inhalation exposure to formaldehyde were
located, but deaths have been observed in animal studies following exposure
to concentrations that would produce intolerable irritation.
What happens when formaldehyde solutions
comes into contact with my skin?
Formaldehyde solutions are considered corrosive to the skin. However, they
have only caused mild to moderate skin irritation in animal studies. There is
little human information on the irritancy of formaldehyde solutions,
although their potential for irritation is widely accepted.
Formaldehyde solutions form corrosive formic acid upon standing. Corrosive
materials can cause severe burns, blistering and permanent scarring of the
skin. Any skin contact may also involve inhalation exposure.
Skin contact with formaldehyde solutions can cause an allergic skin reaction
in some people. Refer to skin sensitization under "What are the long-term
health effects of exposure to formaldehyde solutions?" below."
Formaldehyde solutions may be toxic if absorbed through the skin, based on
an unconfirmed animal toxicity value.
Can formaldehyde solutions hurt my eyes?
Formaldehyde solutions are corrosive to the eyes. Corrosive materials can
cause severe eye damage with permanently altered vision or blindness.
There are several case reports of eye injury occurring when formaldehyde
solutions were accidentally splashed into the eyes. Characteristically,
formaldehyde eye injuries are immediately painful but can leave the eye
looking normal for at least an hour or two after exposure. Over the course of
the next 12 hours, very severe eye damage becomes apparent.
Formaldehyde gas is also irritating to the eyes. The threshold for mild eye irritation may
be as low as 0.01 ppm. Although, continued exposure may result in some acclimatization.
Twelve volunteers exposed for 5 minutes to formaldehyde (composition not specified),
mixed with other non-irritating pollutants, could detect and react to 0.01 ppm, with 0.2
ppm causing light to medium eye irritation, and 0.6 ppm causing medium to severe
irritation. Exposure to 1 ppm formaldehyde gas (generated by heating paraformaldehyde)
for 6 minutes caused slight to moderate eye irritation in 27 volunteers. Thirty-three
volunteers exposed to 0, 0.25, 0.5, 1 or 2 ppm formaldehyde gas (generated from heating
paraformaldehyde) for 90 minutes experienced irritation of the eyes at all concentrations,
with severity increasing with concentration.
What happens if formaldehyde solution is accidentally
swallowed (enters the digestive system)?
Formaldehyde solutions are toxic if ingested, based on animal and human information. Ingestion
of formalin (37-50% water solutions of formaldehyde; 0-15% methanol) in accidental, suicidal or
homicidal cases has caused corrosive burning of the mouth, throat and digestive tract with
vomiting of tissue and blood. Ingested formaldehyde is rapidly converted to formic acid, which can
cause metabolic acidosis, and damage to the liver and kidneys leading to jaundice and swelling of
body tissues. In severe cases, there may be convulsions, central nervous system depression and
death. The fatal dose for formaldehyde in humans is estimated to be about 60-90 mL of formalin
(317-475 mg/kg of formaldehyde assuming a 37% solution of formalin and a 70 kg person). The
presence of methanol may contribute to the overall toxicity of ingested formalin. Ingestion is not a
typical route of occupational exposure.
What are the long-term health effects of exposure to formaldehyde
solutions?
Only very limited information is available on the potential effects from long-term occupational
exposure to formaldehyde. Mixed exposures and/or low numbers of workers studied limit most of
the available studies.
Occupational exposure studies indicate that formaldehyde exposure causes temporary reversible
decreases in lung function but no long-term effects. There is sufficient evidence that formaldehyde
causes nasopharyngeal cancer in humans. There is limited evidence for cancer of the nasal cavity
and paranasal sinuses and strong but not sufficient evidence for leukemia (see "Will formaldehyde
solutions cause cancer?" " below for more information). Formaldehyde is not a respiratory
sensitizer, but can bring on the symptoms of asthma in susceptible individuals, probably due to
irritation of the airways. Human and animal studies demonstrate that formaldehyde solutions
cause skin sensitization.
Nervous system effects have been reported in studies of histology or anatomy technicians
exposed to formaldehyde. However, firm conclusions cannot be drawn from these studies because
of limitations such as concurrent exposures to other chemicals.
NERVOUS SYSTEM: Firm conclusions cannot be drawn about the potential nervous system effects of
formaldehyde. Neurological impairment was reported in two studies of workers (usually histology
and anatomy technicians) exposed to formaldehyde. In all cases, there was concurrent exposure to
other solvents including phenol, xylene, chloroform and ethanol. A third study did not show any
significant neurological effects in a large group of histology and anatomy technicians.
LUNGS/RESPIRATORY SYSTEM: Occupational exposure studies indicate that formaldehyde exposure
causes temporary, reversible decreases in lung function, but no long-term effects. Formaldehyde is
considered a probable respiratory carcinogen (see "Will formaldehyde solutions cause cancer?"
below).
Several studies have evaluated lung function in formaldehyde-exposed particle-board and
plywood workers, workers using acid-hardening paints, embalmers, urea-formaldehyde resin
producers, medical students and anatomy and histology workers. Exposures to formaldehyde
ranged from less than 0.02 ppm to greater than 5 ppm and there were often concurrent exposures
to other substances. In most of the studies, exposure caused temporary reversible decreases in
lung function, but no long-term effects.
RESPIRATORY SENSITIZATION: There is very little convincing evidence that formaldehyde can induce
asthma, given the small number of reported cases in relation to the large number of workers
potentially exposed to formaldehyde. Only a very few of the reported cases have proven positive in
well-conducted bronchial challenge tests. There is generally little correspondence between the
presence of formaldehyde-specific antibodies and the occurrence of asthmatic symptoms in exposed
people. However, the evidence indicates that formaldehyde can bring on the symptoms of asthma in
susceptible individuals, probably through irritation of the airways.
SKIN: Long-term exposure to formaldehyde solutions is expected to cause dry, red, irritated skin
(dermatitis).
SKIN SENSITIZATION: Formaldehyde solutions cause occupational skin sensitization. Once a person is
sensitized, contact with even a small amount of a formaldehyde solution can cause outbreaks of
dermatitis with symptoms such as redness, rash, itching and swelling. This reaction can spread from
the hands or arms to the face and body.
Many cases of allergic contact dermatitis have been associated with exposure to formaldehyde
solutions. Occupational examples include nurses, funeral embalmers and newsprint handlers. In
over 4700 consecutive patients patch tested with an extended standard series of up to 34
chemicals, formaldehyde was the ninth most common cause of allergic reactions, with positive
reactions in 3% of the patients. It is estimated that 3-6% of the population responds positively to
2% formaldehyde. Studies in guinea pigs and mice also prove that formaldehyde solutions cause
skin sensitization.
Will formaldehyde solutions cause cancer?
Formaldehyde is carcinogenic to humans. The International Agency for Research on Cancer has
concluded there is sufficient evidence that formaldehyde causes nasopharyngeal cancer in
humans. There is limited evidence for cancer of the nasal cavity and paranasal sinuses and "strong
but not sufficient evidence" for leukemia. There are many human population studies on the
increase of respiratory cancers in people occupationally exposed to formaldehyde. These studies
have been extensively reviewed elsewhere and are not reviewed here.
Excess numbers of nasopharyngeal cancers were associated with occupational exposure to
formaldehyde in 2/6 cohort studies, 3/4 case-control studies, and in meta-analyses. In addition,
2/6 case-control studies indicated a positive association between occupational exposure to
formaldehyde and cancer of the nasal cavities and paranasal sinuses, while 3 were negative and 1
was weakly positive. Cohort studies of embalmers and other professionals who use formaldehyde
showed some excess risk for brain cancer. However, this risk did not increase with exposure. There
was no increase in risk found for other types of cancer. Some large scale, well-conducted studies
have found an association between formaldehyde exposure and leukemia, while others have not.
In a recent meta-analysis of the incidence of pancreatic cancer in 14 epidemiology studies, a small
but consistent increase was found in studies of embalmers, anatomists and pathologists, but not
in industrial workers, who had higher average and peak exposures. The increased incidence may
be due to better diagnosis in the first group or to exposures to chemicals other than
formaldehyde.
Will formaldehyde solutions cause any problems with my reproductive system?
There is insufficient evidence to determine if formaldehyde causes reproductive toxicity.
In a retrospective study of women wood workers, 288 were not exposed to formaldehyde and 235
were subdivided into 119 low, 77 medium and 39 high formaldehyde exposure. Assignment to an
exposure category was based on self-reporting verified with measured concentrations from own
or a comparable workplace. In the high exposure group, formaldehyde exposure was associated
with a longer time to pregnancy and an increased risk for endometriosis. However, firm
conclusions cannot be drawn from this study due to limitations such as self-reporting bias, the
relatively small number of women studied and concurrent exposures to other potentially harmful
chemicals.
In a study, which is not available in English, menstrual irregularities and higher infertility were
reported in female workers exposed to formaldehyde, based on self-reporting and examinations.
This study is limited by poorly reported methods, self-reporting biases, no accounting for
confounding factors and no definition of infertility.
In a Finnish study of the effects of the father's occupation on the rate of miscarriage,
formaldehyde exposure was not associated with an increase in miscarriages.
Despite limitations, the few animal studies available do not suggest that formaldehyde exposure
will affect fertility.
Will formaldehyde solutions cause effects on an unborn baby?
The available human and animal evidence does not suggest that formaldehyde is a developmental
toxin.
There are several human population studies of adverse pregnancy outcomes in women
occupationally exposed to formaldehyde. Studies that found significantly higher rates of
miscarriages in women occupationally exposed to formaldehyde are all limited by self-reporting of
exposures and by the low number of women studied. The larger studies and those that
determined formaldehyde exposure by evaluation of work task, have not shown an increased risk
of miscarriage. No significant association between formaldehyde exposure and low birth weights
(less than 2500 g) was found in 3 human population studies.
There are many animal studies that have examined the potential developmental toxicity of
formaldehyde. Many of these studies have limitations such as low animal numbers, lack of
detailed information on methods, and lack of information on maternal toxicity. Well-conducted
animal studies do not show developmental effects in the absence of maternal toxicity.
Will formaldehyde solutions act in a synergistic manner with other materials (will its effects be
more than the sum of the effects from the exposure to each chemical alone)?
Several animal studies have exposed animals to formaldehyde in combination with other
carcinogens. In some of these studies, formaldehyde enhanced the effect of other carcinogens,
causing more tumours or faster tumour growth. Animal studies also suggest that formaldehyde
may facilitate respiratory sensitization to other allergens.
Is there potential for formaldehyde solutions to build-up or accumulate in my body?
Formaldehyde does not accumulate. It is a normal intermediate metabolite and is found in all
cells. It is very reactive and readily bonds to proteins and nucleic acids. It has a half-life in the
blood of about 90 seconds and is rapidly metabolized to formic acid (which is excreted in the
urine), converted to carbon dioxide (which is exhaled), or used to synthesize proteins and nucleic
acids.
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