July 2009 – OEL for formaldehyde Policy and Research Division Page 1 of 69

Occupational Exposure Limits for Formaldehyde

1. BACKGROUND

At the March 2007 Board of Directors (―BOD‖) meeting, the Policy and Research 

Division (―PRD‖) received approval to release the Discussion Paper on the 

occupational exposure limits for formaldehyde for consultation (attachment 1). As 

well, the BOD, at their July 2007 meeting, directed the PRD to:

(a) Obtain a formal recommendation from the Occupational Exposure Limit Review 

Committee (―OEL Review Committee‖) on the OELs for formaldehyde; and

(b) Obtain an independent peer reviewer to evaluate whether the summary of the 

health effects contained in the discussion paper accurately reflects the health 

risks to workers, particularly at exposure levels between American Conference of 

Governmental Industrial Hygienists (―ACGIH‖) TLVs and the current BC OELs.

(c) Return with the results of the public consultation on the discussion paper.

The results of the above requests are set out below.

2. SUMMARY OF HEALTH EFFECTS FROM SCIENTIFIC LITERATURE REVIEW

Based on a comprehensive review of available health studies, the weight of scientific 

evidence indicates that workers will not experience any adverse health effects at the 

current BC OELs. There is no evidence that formaldehyde is a cytotoxin, mutagen, 

genotoxin, carcinogen, reproductive or developmental toxin, or causes other short or 

long term adverse health effects at the current BC OELs. 

Cytotoxicity (damage to the cells and tissues of the eyes, nose and throat)

 The weight of evidence indicates that cytotoxic effects – including chemosensory 

irritation of the eyes, nose and throat – do not occur at current BC OELs for 

formaldehyde. 

Mutagenicity/Genotoxicity (damages DNA)

 The weight of evidence indicates that formaldehyde is not mutagenic or 

genotoxic to humans at current BC OELs for formaldehyde.
July 2009 – OEL for formaldehyde Policy and Research Division Page 2 of 69

Carcinogenicity (cancer-causing)

 The weight of evidence indicates that formaldehyde is not carcinogenic to 

humans at current BC OELs for formaldehyde.

Reproductive / Developmental Toxicity (adverse effects to the reproductive system / 

fetal development)

 The weight of evidence indicates that formaldehyde is not associated with 

reproductive or developmental toxicity at current BC OELs for formaldehyde.

Figure 1 below is a summary of the non-adverse and adverse health effects of 

formaldehyde. The weight of evidence indicates that:

 1.0 ppm – the irritant detection threshold – is the dividing line between adverse 

and non-adverse health effects;

 Below 1.0 ppm, adverse health effects are not observed; the odour is detectable 

but not considered annoying or irritating; 

 Adverse health effects commence with chemosensory irritation of the eyes and 

nose at formaldehyde levels at 1.0 ppm or above, followed by cytotoxic effects at 

around 3 ppm (cell and tissue damage) and an increased potential for genotoxic 

and carcinogenic effects at levels in excess of 6 ppm; 

 BC‘s current 8-hour TWA of 0.3 ppm is well below levels capable of causing 

adverse health effects and protects the worker from the pungent, unpleasant 

odour of formaldehyde. 

 BC‘s current Ceiling Limit of 1.0 ppm protects the worker from brief peak 

exposures to the chemosensory irritating effects of formaldehyde. 
July 2009 – OEL for formaldehyde Policy and Research Division Page 3 of 69

Figure 1:

Summary of the non-adverse and adverse health effects of formaldehyde in relation to the current 

WCB occupational exposure limits

3. OEL REVIEW COMMITTEE’S RECOMMENDATION

WorkSafeBC‘s OEL Review Committee, comprised of subject matter experts, met on 

July 19, 2007 to obtain formal endorsement for the occupational exposure limits for 

formaldehyde. Based on the reviews of health effects in the scientific literature, the 

OEL Review Committee unanimously supported the option to retain the current OEL 

of an 8-hour TWA limit of 0.3 ppm and a Ceiling limit of 1.0 ppm. They also agreed

that there are no adverse health effects at the BC OELs.
July 2009 – OEL for formaldehyde Policy and Research Division Page 4 of 69

4. PEER REVIEW

The PRD retained a peer reviewer, Professor Adolf Vyskocil, of the Department of 

Environmental and Occupational Health at the University of Montréal, Québec.

Dr. Vyskocil is a world recognized expert in the fields of occupational hygiene, health 

and chemistry and has authored over 350 scientific papers on the health effects of 

chemical substances. 

The peer reviewer was asked to:

 review the scientific literature on health effects of formaldehyde at levels 

between the current BC OELs and the ACGIH TLVs; and

 review the health effects as stated in the Discussion Paper to ensure they 

accurately reflect what is stated in the scientific literate. 

The peer reviewer confirmed that the summary of health effects outlined in the 

Discussion Paper accurately reflects the health risks to workers for the following 

effects:

 Cytotoxicity

 Mutagenicity/Genotoxicity

 Carcinogenicity

 Reproductive toxicity, and

 Sensitization.

His summary and conclusions of toxicokinetic and health effects is very similar to the 

summary presented in the Discussion Paper. He reiterates the fact that if the 

respiratory tract is not repeatedly exposed to levels that cause cellular or tissue 

damage (cytotoxic effects), exposure to low, non-cytotoxic concentrations of 

formaldehyde at the current BC OELs represents a negligible risk of cancer. The 

peer reviewer confirmed that there is no conclusive evidence that formaldehyde is a 

genotoxin, carcinogen, reproductive or developmental toxin, or causes other long 

term health effects at the current BC OELs. 

The peer reviewer also suggested that additional information be reviewed on 

threshold levels of eye and nasal irritation. As suggested, the scientific literature on 

odour detection and chemosensory irritation was re-examined. Two recent scientific 

reviews (by Lang et al, 2008 and Noisel et al, 2007) were also obtained that looked 

at human exposures to formaldehyde. They concluded that odour 

detection/perception is considered a non-adverse health effect; adverse health 

effects commence with eye chemosensory irritation at the threshold level of 1.0 ppm 

followed by increased adverse health effects around 3 ppm including cell and tissue 

damage, and the potential for cancer-induction at formaldehyde levels in excess of 6 

ppm.
July 2009 – OEL for formaldehyde Policy and Research Division Page 5 of 69

5. STAKEHOLDER FEEDBACK ON THE DISCUSSION PAPER

The PRD received 14 responses to the Discussion Paper from stakeholders.

The majority (10) supported retaining the current OELs of 0.3 ppm 8-hour TWA and 

Ceiling limit of 1.0 ppm. Four responses supported adopting the ACGIH Ceiling limit 

of 0.3 ppm. 

Stakeholders who supported retaining the current limits were industry / employer 

representatives who believe that lowering the OELs to the ACGIH TLV would have 

significant negative impacts and cause closure of BC‘s forest products industry 

dependent on formaldehyde-based adhesives without any corresponding health 

benefit. 

Stakeholders who supported lowering current formaldehyde limits to match those of 

the ACGIH were worker representatives who believe workers must be protected with 

the lowest possible exposure limits. 
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 6 of 69

DISCUSSION PAPER

1. TITLE AND DATE

Changes to the Occupational Exposure Limits for Formaldehyde

2. ISSUE

WorkSafeBC (―WCB‖) is considering whether to adopt the American Conference of 

Governmental Industrial Hygienists (―ACGIH‖) Threshold Limit Value (―TLV‖) for 

formaldehyde

3. BACKGROUND

In general, while occupational exposure limits (―OELs‖) are established according to the 

TLVs adopted by the ACGIH, WorkSafeBC has the authority, in accordance with the 

provisions of section 5.48 of Occupational Health & Safety Regulation (―OHSR‖), to 

develop OELs for specific chemical substances that differ from the ACGIH TLVs. The 

excluded substances were listed in Prevention Policy R5.48-1 for the following reasons:

 The OEL for the excluded substance was more protective than the ACGIH TLV;

 The ACGIH had no TLV for the substance; or 

 Industry was unable to meet the TLV.

Following a period of extensive consultation with stakeholders and research by 

WorkSafeBC staff, formaldehyde was deemed an excluded substance and placed in 

policy. It was established that industry could not meet the TLV. Accordingly, the OEL 

assigned to formaldehyde is less protective than the current ACGIH TLV. 

4. DISCUSSION

In the summer of 2005, the Policy and Research (―PRD‖) advised stakeholders that the 

Board of Directors (―BOD‖) was considering adopting the ACGIH TLV for formaldehyde 

and requested feedback on what steps would need to be taken to achieve the proposed 

limit.

The table below shows the current OELs that are in effect in BC (both an 8-hour TWA 

and a Ceiling Limit) and the TLV (Ceiling Limit only) established by the ACGIH.

Table of Current WorkSafeBC OELs and ACGIH TLVs for Formaldehyde

Current WCB OELs (ppm) ACGIH TLV (ppm)

TWA Ceiling Limit TWA Ceiling Limit

0.3 1.0 --- 0.3

Formaldehyde is listed as a Group 1 carcinogen (―carcinogenic to humans‖) by the 

International Agency for Research on Cancer (―IARC‖) and a Group A2 carcinogen 

(―suspect human carcinogen‖) by the ACGIH. 
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 7 of 69

The PRD undertook a detailed assessment to determine if the current TLV 

recommended by the ACGIH for formaldehyde should be applied in BC workplaces, 

which included: 

a) Meetings with industry and labour representatives;

b) Review of written submissions;

c) Review of the literature on the health effects of formaldehyde; 

d) Comparison of occupational exposure limits, both nationally and internationally;

e) Analysis of workplace exposure data collected by WorkSafeBC and other 

sources; 

f) Tour of a large plant which uses formaldehyde; and

g) Analysis of WorkSafeBC claims data.

a) Meetings with Industry and Labour Representatives:

At the request of industry representatives, two meetings were held with staff from 

WorkSafeBC. The first occurred on September 30, 2005 with industry representatives 

and the second was held on February 5, 2006 with both industry and labour 

representatives (Appendix A).

b) Written Submissions

Industry and Employers:

Responses to the proposal to adopt the ACGIH Ceiling Limit for formaldehyde were 

received from 29 employer stakeholders, with the majority voicing strong opposition to 

the adoption of the ACGIH Ceiling Limit. Opposition was received primarily from the 

large-scale industrial users of formaldehyde (panel board industry, including plywood, 

particle / fibre board, oriented strand board and laminated wood producers), as well as 

from the chemical industry and industry associations. Other users, such as a university 

laboratory manager and a funeral home representative, were also opposed. Support for 

the adoption of the ACGIH Ceiling Limit received a smaller response and a number of 

these respondents either did not use, or were no longer using the substance, or used the 

substance on a small scale. 

The primary reasons expressed by the employer group for opposing the adoption the 

ACGIH Ceiling Limit can be summarized as follows:

 Both the ACGIH and IARC have not kept current with recent toxicological and 

epidemiological evidence;

 There is a lack of substantive evidence that formaldehyde is a cancer-causing agent 

in humans and that it has been misclassified as a ―human carcinogen‖ by IARC; 

 BC already has some of the most stringent exposure limits for formaldehyde, both 

nationally and internationally; 

 Implementation of the ACGIH Ceiling exposure limit in BC workplaces is not feasible;

 A competitive disadvantage would result for BC industries in favour of their 

counterparts in adjacent jurisdictions;

 At least one forest products (panel board) facility in the BC Interior would face 

closure. There may be other facilities facing closure that WorkSafeBC has not been 

apprised of.

A great deal of information was provided by the industry and employer representatives 

(Appendix A). 
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 8 of 69

Labour:

Based on their single written submission, labour was in strong support of adopting the 

ACGIH TLV Ceiling Limit value. The submission is reviewed in Appendix A. 

The primary reasons expressed by labour in support of their position include:

 WorkSafeBC should consider adopting the ACGIH 0.3 ppm Ceiling Limit, along with 

the sensitization and human carcinogen designation, in order to adequately protect 

workers since the current limits are too high; 

 It is important for workers not to be exposed to short duration peak exposures above 

0.3 ppm;

 A Ceiling Limit value of 0.3 ppm will protect workers from the adverse health effects 

of formaldehyde, including the cancer-causing effects;

 Wherever best practices are adopted, a Ceiling Limit is or can be met in BC 

industries.

c) Health Effects of Formaldehyde:

An extensive body of literature exists on both the acute and chronic health effects of this 

chemical. Much new information has become available since the late 1990s including a 

revised model for carcinogenesis, using formaldehyde as a focus. Several expert panels 

have recently re-evaluated the health effects of formaldehyde, including large cohort 

epidemiological studies. Details of these reports are discussed in Appendix B. A 

summary of the acute and chronic health effects is provided below. 

Acute Health Effects:

The primary route of exposure of formaldehyde is through inhalation. There is no 

indication that the substance is absorbed to any extent through the skin. 

Formaldehyde‘s adverse health effects are primarily related to its irritative or 

inflammatory properties. It is a highly reactive chemical that readily reacts with biological 

tissues, particularly the mucous tissues lining the respiratory tract and the eyes. Mucous 

tissues by nature are moist and characterized by a thin-walled cellular (epithelial) layer 

that is highly susceptible to chemical irritation. As a result of its reactivity, inhaled 

formaldehyde is rapidly and almost entirely absorbed by the mucous tissues lining the 

upper respiratory tract, penetrating no farther than the major bronchi of the respiratory 

tract at low or medium concentrations. The mucous tissues of the eyes are also a 

susceptible target. Neither formaldehyde nor its metabolic by-products accumulate to 

any significant extend in the body even at elevated ambient formaldehyde 

concentrations.

1

Localized irritation of mucous epithelial tissues by formaldehyde, if prolonged, can lead 

to localized tissue damage; basically the cytotoxic effects of formaldehyde may result in 

histopathological changes.

2 Evidence indicates that tissue damage in experimental 

animals occurs at airborne formaldehyde concentrations above 4 – 6 ppm. Severe 

effects have been reported following exposure to very high concentrations (in excess of 

 

1

NOTE: Formaldehyde exists naturally at very low levels in cells and tissues in plants, animals and 

humans, a result of normal metabolic processes.

2

 Cytotoxic = toxic to cells; histopathological = damage to the epithelial tissues, including reddening, 

sloughing of cells, leakage of plasma, bleeding, an increase in the number of cells (hyperplasia), 

change in cellular composition (metaplasia), and a breakdown of cellular components, leading to 

cellular death.
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 9 of 69

50 ppm). These effects include pulmonary edema, pneumonia, and death as a result of 

the complete breakdown of the tissues lining the respiratory tract and the lungs.

Recent studies, involving testing of human response to airborne formaldehyde, indicate 

that due to the pungent and unpleasant odour of formaldehyde, it has been difficult to 

distinguish: 

a) mucous tissue irritation (localized changes to the cells and tissue) from 

b) chemosensory stimulation which involves stimulation of local nerve endings. 

Chemosensory stimulation will not necessarily lead to cellular irritation and any 

histopathological changes. Earlier studies conducted on establishing levels of irritation 

experienced by test subjects failed to distinguish actual mucous tissue irritation from 

chemosensory irritation. Several expert panels have recently reviewed and researched 

this apparent dichotomy, and have concluded that cytotoxic effects of formaldehyde do 

not appear to occur at levels below 0.75 to 1.0 ppm formaldehyde. A level of 1.0 ppm is 

considered the no-observed-adverse-effect-level (NOAEL)3for nasal injury in humans. 

This is further supported by the fact that at concentrations below 1.0 ppm, symptoms 

disappear very quickly, underlying the non-adversity of the irritating effects at low 

concentrations.

Appendix C provides further details on the chemical characteristics of formaldehyde, 

routes of entry, biochemical pathways, and adverse health effects associated with 

exposure to the substance. 

Chronic Health Effects:

Evidence on the adverse effects in humans based on long term (chronic) exposures to 

formaldehyde is minimal. Information on chronic health effects is based almost entirely 

on animal studies. Repeat dose inhalation studies have been conducted on mice, rats 

and monkeys. Cellular (histopathological) changes are observed in all species with 

slight damage to the tissues of the nose and upper respiratory tract at concentrations at 

2 – 3 ppm, with more pronounced damage at levels up to approximately 6 ppm. Severe 

cellular damage to respiratory tract tissue – severe rhinitis, tissue death and extensive 

hyperplasia4– occurs at concentrations 6 ppm and above. The no-observed-adverseeffect-level (NOAEL3

) for respiratory tract irritation in experimental animals is claimed to 

be in the 1 – 2 ppm range. A level of 1.0 ppm is considered the NOAEL3for injury to the 

nasal passages in humans. 

Mutagenicity & Carcinogenicity:

IARC has evaluated formaldehyde and determined that there is sufficient evidence that 

formaldehyde be classified as a human carcinogen. On the other hand, the ACGIH has 

determined that formaldehyde is not a proven human carcinogen but a suspect human 

carcinogen. This is also the conclusion of a number of other jurisdictions and reference 

organizations, as detailed in Appendix B.

According to current information, formaldehyde is shown to be genotoxic agent5at 

concentrations that cause severe tissue damage. This is primarily due its activity as a 

 

3

 Postscript: erratum noted by Dr. Vyskocil – NOAEL should read LOAEL (lowest-observed-adverseeffect-level

4

A general term for an increase in the number of the cells of an organ or tissue due to a number of 

causative factors including, increased demand, chronic inflammatory response, and other triggers.

5

Toxic to the genetic material of the cell including DNA
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 10 of 69

reactive alkylating agent6and like other alkylating agents, a likely candidate for being a 

mutagen or a carcinogen. Accordingly, formaldehyde is classified as a mutagen and

also a potential carcinogen. 

More specifically, it has been shown that while formaldehyde is clearly an experimental 

animal carcinogen of the upper respiratory tract, it is not of any other tissues or organs; 

that is, tissues must be in direct contact with formaldehyde in order to induce tumorous 

growth. Hence, its systemic effects (e.g., liver, kidneys and other organs and tissues at

distance from the site of contact) are negligible when the route of entry is via the 

respiratory tract. Nasal tumours most probably arise as a consequence of pronounced 

localized chronic tissue irritation of the nasal passages in association with genotoxic 

effects at the cellular level – a ―site-of-contact‖ effect. Genotoxic effects include the 

formation of DNA-protein cross-links and other indicators of genetic damage. 

As detailed in Appendix B, several expert panels recently re-evaluated the 

epidemiological studies conducted in the 1980s and early 1990s – including the cohort 

studies on which IARC has based its conclusions. The expert panels conclude that the 

evidence falls short in providing conclusive proof that formaldehyde exposure results in 

nasopharyngeal cancer in humans. Accordingly, jurisdictions, such the United Kingdom 

and German occupational health and safety authorities and the European Scientific 

Committee on Occupational Exposure Limits (―SCOEL‖), have classified formaldehyde 

as a suspect human carcinogen similar to the ACGIH due to the insufficiency of the 

evidence for cancer induction in humans but that it is capable of inducing cancers in 

experimental animals.

Reproductive Toxicity:

There is no evidence that formaldehyde is a reproductive toxin.

Sensitization:

In humans, formaldehyde is classified as a skin sensitizer due to its direct irritative 

effects on tissues and its ability to induce an immune response at the site of contact. 

Formaldehyde is not considered a significant cause of occupational asthma. 

Experimental evidence shows that exposure of asthmatic individuals to formaldehyde 

does not change the nature or status of the asthmatic condition. 

Summary of the adverse health effects of formaldehyde:

Figure 1 summarizes current knowledge on the adverse health effects and carcinogenic 

potential of formaldehyde in experimental rats and humans relative to airborne exposure 

levels. An ―effect level‖ – as shown in the figure 1 – is a response elicited by an 

experimental rat or human relative to the concentration in air, and includes eye irritation, 

nasal irritation, level of tolerance (human), and cytotoxic and carcinogenic responses. 

The term ―subjective‖ in the figure is a verbal or similar communicative response by the 

human subject to the tester (―I can smell / detect formaldehyde‖); an ―objective‖ 

response is one that can be measured and quantified such as a record of the rate and 

frequency of blinking. An objective response is far superior, scientifically, to a subjective

response. 

 

6

A chemical that acts on the genetic material in the nucleus of the cell – deoxyribonucleic acid (DNA), 

causing mutagenic or carcinogenic effects
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 11 of 69

Of note is that formaldehyde levels in air must be above 6 ppm in order to initiate the 

growth of tumours – both benign and cancerous. At concentrations at 10 ppm and 

greater, cancerous tumours are well established. Humans are not able to tolerate levels 

of exposure to airborne formaldehyde above 4 – 5 ppm. 

WorkSafeBC‘s current Ceiling Limit of 1.0 ppm is at the subjective eye irritation level and 

below the objective eye irritation level of 1.7 ppm for humans. The current TWA of 0.3 

ppm is significantly lower than both subjective and objective eye irritation levels and 

below nasal irritation levels based on the most current experimental information. 

Figure 1: Summary of effects levels of formaldehyde in humans and experimental 

rats 

1 Means an increase in the number of cells of an organ or tissue

2 Means the replacement of one cell type with a differentiated cell type – usually due to chronic irritation 

and inflammation; it is reversible and a natural protective response allowing the substitution of cells that 

are better able to survive where a more fragile cell type is likely to succumb

3 Means abnormal disorganized growth in a tissue or organ; also know as a tumour which may be either 

benign or malignant

4

Edema = severe rhinitis (―a very runny nose‖)

d) OELs for Formaldehyde in BC and Other Jurisdictions

Regulated occupational exposure limits for formaldehyde from all Canadian as well as 

American and international jurisdictions are portrayed in Table 1.
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 12 of 69

Table 1: Current and Scheduled Regulated OELs for Formaldehyde: Canadian and 

Other Jurisdictions

Jurisdiction 8-Hour TWA 

(ppm) or 

equivalent

Short-Term 

Exposure Limit –

STEL (ppm) or 

equivalent

Ceiling 

Exposure 

Limit – “C” 

(ppm) or 

equivalent

Canadian Jurisdictions

ACGIH7

 Manitoba

 Nova Scotia

 PEI

 Newfoundland and Labrador

0.3

Alberta 0.75 2

British Columbia 0.3 1

New Brunswick 0.5 1.5

Northwest Territories8

0.3

Ontario 1 1.5

Québec 2

Saskatchewan 0.3

Yukon 1 2

Canada Labour Code (Federally 

regulated workers)

0.3

American Jurisdictions

California 0.75 2

Oregon 0.75 2

Washington State 0.75 2

International Jurisdictions

Germany9

0.3 0.6 1

United Kingdom 2 2

Netherlands10 1 1.5

 

7

These four jurisdictions automatically adopt the annual ACGIH TLV updates.

8

Based on the 2001 TLVs issued by the ACGIH.

9

The Deutsche Forschungemeinschaft (DFG) endorses this MAK Commission value. Note: the STEL 

and Ceiling Limit values indicated are based on DFG‘s protocol for establishing these values 

(multipliers).

10 Not legally binding at this time; under review; an 8-h TWA of 0.5 ppm and STEL of 1 ppm is being 

considered.
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 13 of 69

Jurisdiction 8-Hour TWA 

(ppm) or 

equivalent

Short-Term 

Exposure Limit –

STEL (ppm) or 

equivalent

Ceiling 

Exposure 

Limit – “C” 

(ppm) or 

equivalent

France 0.5 1

Switzerland 0.5 1

Norway 0.5 1.5 1

Sweden 0.5 1

Finland 0.3 1

Denmark 0.3

Australia 1 2

New Zealand 1

TWA: the time weighted average (TWA) concentration of a substance in air which may not be exceeded 

over a normal 8 hour work period.

STEL: the time weighted average (TWA) concentration of a substance in air which may not be exceeded 

over any 15 minute period, limited to no more than 4 such periods in an 8 hour work shift with at 

least one hour between any 2 successive 15 minute excursion periods.

Ceiling: the concentration of a substance in air which may not be exceeded at any time during the work 

period.

With respect to establishing an OEL, much new information has come forth over the last 

6 to 8 years as a number of jurisdictions have completed their reviews on formaldehyde, 

or are currently in the process of considering appropriate exposure limits for 

formaldehyde – be it an 8-hour TWA, a Short Term Exposure Limited (―STEL‖), or 

Ceiling Limit, or a combination of the three. Quebec and Germany have completed their 

reviews as have Australia, the United Kingdom, Holland and the Nordic nations.

As Table 1 indicates, a Ceiling Limit of 0.3 ppm with no 8-hour TWA limit has been 

adopted in Denmark, and in several Canadian jurisdictions, including Manitoba, 

Saskatchewan, Nova Scotia, Newfoundland, PEI and the Northwest Territories, as well 

as for federally regulated workers. Quebec has a Ceiling Limit of 2 ppm with no 8-hour 

TWA limit. All other provinces and other jurisdictions shown have a combination of 8-

hour TWAs, STELs and Ceiling Limits.

BC, along with Finland and Germany have the lowest 8-hour TWAs at 0.3 ppm. 

Germany and the Nordic countries along with BC enforce a Ceiling Limit of 1.0 ppm. 

Ontario is currently has a TWA of 1.0 ppm and STEL of 2.0 ppm which came into effect 

March 31, 2006. Effective December 31, 2007, Ontario will forego the TWA limit and 

adopt a more protective STEL (dropping from 2.0 to 1.0 ppm). They will also adopt a 

Ceiling Limit of 1.5 ppm. 

US jurisdictions neighbouring BC prescribe less protective OELs. Washington State and 

Oregon enforce an 8-hour TWA of 0.75 ppm and a STEL of 2.0 ppm; no Ceiling Limit is 

prescribed. 

Overall, BC has one of the lowest 8-hour TWA OELs among the major jurisdictions 

along with a Ceiling Limit OEL that is also among the lowest. A Ceiling Limit of 1.0 ppm 
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 14 of 69

is more protective than a STEL of 1.0 ppm. Hence, notwithstanding the jurisdictions that 

have adopted the ACGIH Ceiling Limit TLV, the current OELs in BC are some of the 

most protective in all jurisdictions. 

The German occupational health and safety authority takes the position that 

formaldehyde does not significantly contribute to human cancer provided the MAK value 

(8-hour TWA) of 0.3 ppm is observed and the Ceiling Limit of 1.0 ppm is not exceeded. 

Several reference agencies, including the German MAK Commission and the Working 

Group on Action to Control Chemicals (―WATCH‖) Committee of the UK Health & Safety 

Executive, make the following observations:

 IARC‘s classification of formaldehyde as a human carcinogen is not supported;

 IARC has been selective in their review; a number of epidemiological studies not 

supportive of IARC‘s position were not included in their 2004 report;

 The avoidance of cellular damage and sustained regenerative proliferation are 

decisive factors for establishing an appropriate exposure limit;

 In the low dose range – less than 1.0 ppm – the toxic effects of formaldehyde on the 

genetic material (―genotoxic effect‖) play only a minimal role in its carcinogenic 

potential so that no significant contribution to human cancer risk is expected in the 

low dose range;

 Cancer risk factors become of concern only when formaldehyde levels exceed 2 – 3 

ppm on a chronic or long term basis;

 With respect to the strong and pungent odour of formaldehyde, the ACGIH did not 

distinguish sensory stimulation from cellular irritation in their recommendation of a 

0.3 ppm TLV Ceiling Limit; and

 Eye irritation – which can be measured and quantified experimentally – unlike nasal 

irritation, is considered the most appropriate indicator of the irritative nature of 

formaldehyde and a more objective determinant of an appropriately assigned 

exposure limit.

The reference agencies, based on recent re-evaluations of the scientific literature on 

controlled nasal and eye irritation studies, conclude that a level of 1 ppm avoids eye 

irritation in a majority of test subjects and that nasal irritation is avoided if formaldehyde 

concentrations are kept below 2 ppm. As a result, airborne levels of formaldehyde 

below 1 ppm are considered low enough to protect workers against nasal tissue 

damage, and consequently, also against a potential risk of nasal cancer. In 

consideration of these factors, an 8-hour TWA of 0.3 ppm was adopted in Germany.

Furthermore, Paustenbach et al. 1997 concluded that a level of 1 ppm formaldehyde 

would avoid eye irritation in at least 75% and up to 95% of exposed workers. In another 

very recently published report, Arts et al. 2006 re-evaluated eye and nasal irritation data 

and concluded that when minimal/mild/slight irritation is taken as a cut off level, eye and 

nasal irritation were found at formaldehyde levels of greater than or equal to (≥) 1 ppm 

and ≥ 2 ppm, respectively.

Additional information pertaining to the findings of the reference agencies can be found 

in Appendix B.

e) Worker Exposures to Formaldehyde in British Columbia and other Locations:

Sampling data collected by WorkSafeBC over a period of 15 years (1990 to 2005

inclusively) indicate that worker exposure to formaldehyde is likely to occur primarily in 

the forest panel board manufacturing sector (plywood, particle / fibre board, oriented 
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 15 of 69

strand board, laminated wood products manufacturing), resin manufacture, acute care 

hospitals, university and other laboratories, and funeral homes. A compilation of 

compliance sampling data collected by WorkSafeBC over this time frame is included in 

Appendix D along with exposure data from other sources, including Ontario, Quebec, 

and the Netherlands. 

The exposure data indicates that overall, exposure levels have decreased over time as 

improved control and procedural measures have been implemented. This is particularly 

evident when one compares readings taken in the early 1980s are compared with those 

in the late 1990s. 

The results indicate that industries in which exposure levels were predominantly below

the current 0.3 ppm 8-hour TWA exposure limit include:

 Foundries;

 Resin manufacturing; and

 Plywood manufacturing.

Industries in which the current 0.3 ppm 8-hour TWA exposure limit was exceeded at 

times include (range of exposures shown):

 Paperboard & cardboard manufacturing (0.04 – 0.38 ppm);

 Laminated wood products manufacturing (0.24 – 0.38 ppm);

 Pressed / panel particle / fibre board manufacturing (0.07 – 5.00 ppm);

 Oriented strand board manufacturing (0.03 – 0.32 ppm);

 Funeral homes (none detected to 0.74 ppm);

 University laboratories (0.52 – 1.15 ppm);

 Hospitals & medical clinics and laboratories (0.02 – 1.35 ppm); and

 Poultry hatcheries (0.1 – 0.35 ppm). 

In 2004, Quebec‘s Institute de Reserche Robert Sauvé en Santé et en Sécurité du 

Travail (IRSST) published a report on the health impact of formaldehyde in the 

workplace, at a cost of approximately $1 million, with specific focus on the panel board 

industry, namely oriented strand board, medium density fibre board, particle board 

plants. This study demonstrates a similar worker exposure pattern to formaldehyde as 

seen in BC panel board plants. Proximity to the press (a key component of the panel 

board process and found in all plants) resulted in exposures in excess of 0.3 ppm, at 

times exceeding 1.0 ppm or more. In general, exposures were highest in particle board 

and medium density fibre board plants – generally in excess of the 8-hour TWA 

exposure limit of 0.3 ppm.

In order to determine if the Ceiling Limit for formaldehyde is being exceeded an 

electronic instrument capable of instantaneous read-out must be used. The historical 

data presented in this report is based on sampling equipment that is limited to providing 

only time-weighted-average (TWA) readings. Datalogging electronic equipment was not 

available for use as personal exposure monitors for formaldehyde until very recently.

11

As such, all of the 500+ data points of WorkSafeBC‘s exposure data are TWAs of 

varying duration – from 10 to approximately 480 minutes (8-hour). In essence, a STEL 

is a 15 minute TWA. TWA readings are an integrated average of all the readings within 

the defined sampling period. TWA readings just below the Ceiling Limit value (1 ppm) 

 

11 More recently, personal monitoring equipment capable of datalogging real-time exposure data including 

peak transient exposures has become commercially available (cost estimate: US$4000+ ea).
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 16 of 69

will typically include spikes or excursions above 1 ppm; these spikes will not be 

recorded, however. 

f) Plant Tour:

WorkSafeBC staff (occupational hygienists from the Policy and Research Division and 

the Worker and Employer Services Division) conducted a walk-through survey of a 

medium density fibre board plant. Details of the survey are provided in Appendix B. 

g) WorkSafeBC Compensation Claims Data – Formaldehyde Exposure:

A review of WorkSafeBC‘s data on occupational disease claims over the period of 1990 

to 2005, inclusively, indicates that about 26 claims were classified as being 

formaldehyde-related. Most of the claims appear to be associated with exposures 

sustained during spills of formaldehyde solutions (formalin), and exposures to 

formaldehyde-based resins and adhesives, resulting in localized skin irritation, possible 

allergic contact dermatitis, and upper respiratory tract irritation, as a result of skin contact 

or inhalation of formaldehyde vapours, respectively. None of the claims appear to be the 

result of chronic (long term) exposure to airborne formaldehyde. The Quebec 

Commission on Health and Occupational Safety report similar findings on formaldehyderelated claims for Quebec workers. 

There are no recorded incidences of upper respiratory tract cancers recorded for 

workers in BC that can be causally linked to formaldehyde exposure.

5. OPTIONS AND IMPLICATIONS

Based on the analysis of findings, two options for exposure limits for formaldehyde in BC 

workplaces have been developed:

Option 1 – Status Quo

Under this option the 8-hour TWA limit and Ceiling Limit would remain the same at 0.3 

and 1.0 ppm, respectively. 

Implications:

 Under this option BC‘s current exposure limits for formaldehyde would remain among 

the lowest of the currently regulated exposure limits in the western industrialized 

world;

 The current exposure limits would remain lower than the exposure limits in place at 

proximate jurisdictions including Alberta, Washington State, Oregon and California; 

 The current exposure limits would remain lower than those imposed by other 

Canadian jurisdictions with a significant panel board industry, including Ontario and 

Quebec; 

 BC has a similar 8-hour TWA limit and Ceiling Limit to that adopted in Germany 

where the OELs for formaldehyde were recently reviewed;

 A substantial body of scientific evidence indicates that BC‘s current exposure limits 

will protect workers from the adverse health effects of formaldehyde;

 According to a majority of expert panels, BC‘s current Ceiling Limit of 1.0 ppm is 

protective from the irritative properties of formaldehyde, providing an acceptable 

margin of safety;
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 17 of 69

 WorkSafeBC‘s current Ceiling Limit of 1.0 ppm is at the subjective eye irritation level 

and below the objective eye irritation level of 1.7 ppm for humans. The current 8-

hour TWA of 0.3 ppm is significantly lower than both subjective and objective eye 

irritation levels and below nasal irritation levels based on the most current 

experimental information;

 This option will simplify exposure monitoring of workers allowing the use of standard 

occupational hygiene sampling methods that measure time-weighted-average 

(TWA);

 Employer representatives – particularly from the forest products / panel board sector 

– would likely support this option; and

 Organized labour would likely not support this option.

Option 2 – Adopt the Ceiling Limit recommended by the ACGIH

Under this option, the current 8-hour TWA limit would be withdrawn, and the Ceiling

Limit reduced from 1.0 to 0.3 ppm.

Implications:

 Adoption of a Ceiling-only exposure limit would place BC, along with Manitoba, Nova 

Scotia, Prince Edward Island, Northwest Territories, Newfoundland / Labrador and 

Denmark, among those jurisdictions with the lowest exposure limit among all western 

industrialized nations;

 The ACGIH is the only organization that has recommended an exposure limit based 

solely on a Ceiling-based exposure limit; the other four reference organizations, 

namely the Dutch Expert Committee (DECOS), the German MAK Commission, the 

European Union Scientific Committee for the Occupational Exposure Limits to 

Chemical Agents (SCOEL), and the Australian National Industrial Chemicals 

Notification and Assessment Scheme (NICNAS) Committee have recommended

both 8-hour TWA OELs and STELs for formaldehyde;

 Fibre and particle board plants will not be able to comply with this option due to the 

limitations placed on the operations by a Ceiling-only exposure limit. Currently, full 

shift exposures can approach the current 8-hour TWA exposure limit of 0.3 ppm; the 

most transient of exposures, including spikes of several seconds or less above 0.3 

ppm, would place the plant in non-compliance;

 The Funeral home industry and medical facilities will find it difficult to comply with this 

option. Exposures typically are of short duration; opening a container of formalin is 

likely to result in an exposure exceeding a momentary spike of 0.3 ppm;

 Employer representatives – particularly from the forest products / panel board sector 

– will likely not support this option; and

 Organized labour will likely support this option.

6. RECOMMENDATION

The PRD recommends Option 1 which is to retain the 8-hour TWA limit of 0.3 ppm and a 

Ceiling Limit of 1.0 ppm. 

Formaldehyde is an important industrial chemical used worldwide in the manufacture of 

resins, particle, fibre and oriented strand boards, plywood, leather goods, paper, 

pharmaceuticals and a myriad of other products. Formaldehyde has been exceptionally 

well studied, particularly over the last decade, and health effects have been well defined

in terms of specifying a safe level of exposure for both workers and the public. The 
Attachment 1

July 2009 – OEL for formaldehyde Policy and Research Division Page 18 of 69

current 8-hour TWA and Ceiling Limits provide an adequate level of protection for 

workers exposed to the substance as long as effective control measures are in place. 

7. CONSULTATION

Stakeholders are invited to provide feedback on this discussion paper.

Stakeholder comments will be accepted until 4:30 pm on Friday, June 29, 2007. When 

responding, please provide your name, organization, and address. Comments may be 

sent by mail, fax, or email to:

By mail: Formaldehyde OEL Study

Policy and Research Division

WorkSafeBC

P.O. Box 5350, Stn. Terminal

Vancouver, BC V6B 5L5

By fax: 604 279-7599

By email: regquery@worksafebc.com

WorkSafeBC‘s governing body, the Board of Directors, will consider the comments 

submitted by stakeholders before making a decision. 

Please note that all comments become part of the Policy and Research Division‘s 

database and may be published, including the identity of organizations and individuals 

participating on behalf of organizations. The identity of those who have participated on 

their own behalf will be kept confidential according to the provisions of the Freedom of 

Information and Protection of Privacy Act. 
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 19 of 69

Following the notification letter sent to stakeholders in August 2005 the PRD received 

numerous responses from both labour and employer representatives. All responses, 

except one, were received from the employer group. Table A1 summarizes the 

responses by the representatives from various industries and organizations as well as 

from small or independent employers such as photography processing labs, funeral 

homes. Responses were received by email as well as by mail. The industry association 

along with the chemical / resin & coatings manufacturers and panel board industry 

collectively provided a very comprehensive package of information on the health effects 

of formaldehyde, including critical reviews of the scientific literature. One written 

submission was received from labour.

The majority of the submissions were not in support of adopting the ACGIH Ceiling Limit 

of 0.3 ppm with no prescribed 8-hour TWA limit.

Table A1: Consultation Submissions – by Industry, Associations and Independent 

Employers. Responses: those that Approve, Oppose, or have a Neutral Response 

to the Adoption the ACGIH TLV

Industry, Organizations, Small / Independent 

Employers

Opposed Approve Neutral

Panel board including: plywood, particle board, 

oriented strand board; laminated wood

5 1

Resin & Coatings Manufacture 2 1 2

Chemical Manufacturing 1 1

Industry / Employer Association 7

Miscellaneous12 2 2 5

Labour Organization 1

Total 17 6 7

Meetings with Stakeholders

Meetings with Industry Representatives:

At the request of industry representatives, two meetings were held with staff from the 

PRD. The first occurred on September 30, 2005 and the second was held on 

February 5, 2006.

 

12 Includes photo labs, funeral homes, mortuaries, veterinary clinics, poultry hatcheries, universities, 

foundries.
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 20 of 69

September 30, 2005 Meeting:

Representatives of the following forest products sector, chemical manufacturers and 

industry associations attended:

Composite Panel Association

Hexion Specialty Chemicals, Inc.

Western Fraser Timber Co. Ltd.

Northern Engineered Wood Products Inc.

Engineered Wood Association (APA)

CanPar Industries

Canadian Plywood Association

Dynea Inc.

Methanex Corp.

Formaldehyde Council Inc.

Representatives came from BC, Quebec, Ontario, Washington State and Ohio. The 

delegation provided an overview of the industry‘s position on the health effects of 

formaldehyde with a critique of ACGIH‘s rationale for establishing the Ceiling Limit TLV 

for formaldehyde. An extensive number of supportive studies were distributed. These 

are reviewed in Appendix B.

February 5, 2006 Meeting

The second meeting provided an opportunity for the industry representatives to discuss 

details of the earlier meeting with worker representatives.

Employer representatives:

Composite Panel Association

Hexion Specialty Chemicals

Western Fraser Timber Co. Ltd.

Northern Engineered Wood Products Inc.

Engineered Wood Association (APA)

CanPar Industries

Canadian Plywood Association

Dynea Inc.

Worker representatives:

BC Federation of Labour

IWA / Steelworkers Union

BC Nurses Union

Construction Industry Training Institute, Building Trades

The industry representatives maintained that the basis for carcinogenicity of 

formaldehyde to humans is not well founded, and that the epidemiology is inconsistent in 

demonstrating causality as to the types and patterns of cancers associated with 

formaldehyde. They mentioned that the National Cancer Institute (―NCI‖) – in response 

to recent criticism from the scientific community – is planning to re-evaluate earlier 

cohort studies on the association of nasopharyngeal cancer and formaldehyde in 

workers. 

Both labour and industry representatives discussed the feasibility of achieving 

compliance if the ACGIH Ceiling Limit is adopted. Industry representatives maintained
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 21 of 69

that the panel board and plywood industry would likely not be able to achieve 

compliance with an exposure limit based solely on a ceiling limit value. Labour offered 

the comment that users such as hospitals would likely be able to comply. 

A Review of the Submissions

Generally, employers would like to retain the current status as an excluded substance 

with an 8-hour TWA of 0.3 ppm and Ceiling Limit of 1.0 ppm. Worker representatives 

would like to see the ACGIH Ceiling Limit of 0.3 ppm adopted with no specified 8-hour 

TWA limit. Salient points of submissions from both parties are outlined below.

Worker Submissions

In a written submission by the BC Federation of Labour, labour‘s position remains in 

support of the ACGIH Ceiling Limit of 0.3 ppm for formaldehyde. The submission, dated 

March 23, 2006 entitled: Formaldehyde OEL, reports the following:

 It is important to avoid short duration peak exposures above 0.3 ppm;

 The rationale for limiting exposure to below 0.3 ppm is due to the increased risk of 

both acute and chronic respiratory effects as well as the need to minimize the risk of 

a carcinogenic effect;

 The health effects of exposure to formaldehyde above 0.1 ppm TWA and peak 

exposures (ceiling limits) over 0.3 ppm are well documented in the literature;

 Levels of exposure above 0.1 ppm cause irritant effects and short duration 

exposures above 0.3 ppm induce pathological effects that increase risk of cancer;

 In a study at a plywood plant it has been shown that where workers were exposed to 

levels above 0.8 ppm asthma symptoms increased;

 Peak exposures below 0.3 ppm are identified as necessary to prevent histological 

damage which will increase the risk of nasopharyngeal cancer, the target area of this 

known human carcinogen; and

 WorkSafeBC must adopt the ACGIH 0.3 ppm Ceiling Limit, along with the 

sensitization and human carcinogen designation, as well as the as-low-asreasonably-achievable (―ALARA‖) requirement. 

Labour‘s concern about the health effects of formaldehyde is not limited to the forest 

products industry. Concern is also expressed about protecting the health of workers 

who may also be exposed to high formaldehyde levels in the health care industry. 

Labour‘s submission offers the following comments regarding the achievability of a 0.3 

ppm Ceiling Limit by industry:

 Formaldehyde exposure in various industries has been steadily reduced over the 

years;

 Data from major users – including plywood manufacturers in the US, indicates that 

25 years ago levels were in the 0.35 to 0.38 ppm range; these levels are now lower;

 A study on Quebec particleboard plants indicate levels are below or near 0.1 ppm

and below the 0.3 ppm ceiling in many locations, and that levels measured in New 

Zealand plants had a geometric mean of 0.06 ppm, well below the proposed 

exposure limits.
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 22 of 69

They conclude that whenever best practices are adopted the proposed limits are or can 

be met in BC industries. The report states that ―determining achievability must be based 

on best practices, not on the worst ones‖. 

With respect to achieving compliance, labour would have no concerns: 

 With employers applying for a variance from WorkSafeBC if individual plants have 

difficulty achieving the proposed Ceiling Limit and can demonstrate that they cannot 

comply;

 With the use of respiratory protection, as opposed to engineering controls, to protect 

the most highly-exposed workers assigned to areas where compliance with the 

Ceiling Limit may not be achievable (e.g. press operators, maintenance workers) and 

where a variance from WorkSafeBC has been obtained.

Employer Submissions

In several written submissions, including a PowerPoint presentation at the September 

2005 meeting with PRD staff, spokespersons for the associations and a number of 

individual companies representing the forest products industry acknowledged that there 

is a need to ensure that the exposure limit defined for formaldehyde provides an 

appropriate level of short- and long-term health protection for workers in BC, but that 

there is also a need to ensure that the cost of complying with a regulation does not 

threaten the industry's competitive position, either with respect to its Canadian 

counterparts or its significant export markets, particularly the US. 

The concerns raised by the employers fall into three distinct categories: health issues, 

economic issues, and technical issues, as follows:

a) Overriding perspective

 The weight of scientific evidence does not indicate that lowering the standard 

from the current OELs would provide any further measure of worker protection;

 BC‘s OELs are among the lowest in any jurisdiction;

 A Ceiling Limit of 0.3 ppm is unnecessarily low, economically and technically 

impossible to meet;

 Adoption of the 0.3 ppm Ceiling Limit may result in major plant closures and job 

losses in BC.

b) Health Issues

 Formaldehyde is produced by the human body as part of normal metabolic 

processes;

 It is a natural by-product of all life forms, including plants; 

 ACGIH seeks to eliminate virtually all sensory/discomfort effects with the 0.3 ppm 

Ceiling Limit;

 Concerns with sensory irritation are addressed by WorkSafeBC‘s existing 8-hour

TWA and Ceiling Limit;

 Quebec‘s IRSST 2004 study on formaldehyde, commissioned by the Quebec 

Commission of Health & Safety – CSST, is a significant contributor in 

understanding the irritation threshold and sheds new light on earlier studies 

conducted in the 1980s and which formed the basis for ACGIH‘s current TLV. 

This study examined more than 2,000 workers in the wood products 
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 23 of 69

manufacturing industry in Quebec and concluded that an exposure level below 

0.75 ppm would not provide improved health protection to workers;

 The stakeholders note that the ACGIH recommendation of a Ceiling Limit of 0.3 

ppm was based on even the mildest irritation, and that the ACGIH did not 

consider the quality of the studies; 

 They point out that other researchers have concluded that sensory irritation at 

levels below 1.0 ppm is often difficult to distinguish from responses experienced 

in controls; 

 Reports of irritation below 0.3 to 0.5 ppm were too unreliable to attribute to 

formaldehyde alone;

 Eye irritation does not become significant until at least 1.0 ppm is reached;

 They pointed out that the IRSST concluded that a ceiling value of 1 ppm for 15 

minutes was appropriate to prevent moderate, although transitory, eye irritation;

 The stakeholders referred to a very recent study by researchers (Arts et al, 2006) 

from the Netherlands Organization for Applied Scientific Research (TNO) 

published March 2006 which evaluated sensory irritation relative to 

carcinogenicity regarding inhaled formaldehyde and pointed out the following 

factors;

o The subjectively measured sensory irritation threshold levels in humans 

were assessed relative to findings obtained in animal studies;

o Using Benchmark Dose Analysis it was estimated that at 1 ppm, 9.5% of 

healthy volunteers experienced moderate (i.e., annoying) eye irritation;

o Subjective testing does not exclude the perception factor or trigeminal

nerve stimulation (this is distinguished from actual irritation – it is merely 

that the subject detects the presence of formaldehyde); this is an 

important consideration in that formaldehyde has a very strong odour; 

o Furthermore, respiratory tract irritation can be either a localized pathophysiological response to a chemical (direct localized effect) or a 

chemosensory effect – interaction with local nerve endings (nervus 

trigeminus) – the trigeminal effect;

o Trigeminal stimulation will not necessarily lead to cellular or tissue 

damage;

o In several of the studies assessed, the control or ―0‖ ppm test condition 

was missing;

o Based on long-term inhalation studies in animals, a level of 1 ppm is 

considered the no-observed-adverse-effect-level (NOAEL) for nasal 

injury;

o They conclude that at levels less than 1 ppm where the prevalence of 

sensory irritation is minimal both in incidence and degree, risks of 

respiratory tract cancer are considered to be negligibly low.

 The employer group pointed out that the evidence supporting an association 

between formaldehyde exposure and nasopharyngeal cancer is highly 

questionable;

 Formaldehyde is not likely to cause cancer in the upper respiratory tract when 

there is no cytotoxic effects;

o Tumours development in experimental animal studies occurs at 

concentrations that cause severe local irritation of the upper respiratory 

tract (5 – 6+ ppm), including cell death followed by an increase in cell 

proliferation and damage to the genetic material;
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 24 of 69

 It was pointed out that IARC based its classification on a large cohort study by 

the NCI involving 25,000+ workers followed over time;

 Recent re-evaluations of the epidemiological data by non-NCI researchers of NCI 

data indicates that:

o Nasopharyngeal cancer is rare – 10 cases were found in the 25,000 

worker cohort (representing 10 plants);

o Most of these cancers came from one specific plant (six out of 10 cases) 

with high exposures (average exposures above 1 or 2 ppm with frequent 

peak exposures at 4+ ppm);

o Three of the cancer cases were workers employed for less than one year 

at the plant;

o The authors referenced by the employer representatives (i.e., Marsh et al

– several papers) could not support NCI‘s suggestion of a causal 

association between formaldehyde exposure and mortality from 

nasopharyngeal cancer; they found no such association;

o Furthermore, there was a less than expected mortality rate for 

nasopharyngeal cancer at the other nine plants;

 In response to these critiques of its earlier studies, NCI is planning a reevaluation of its earlier studies and a report is expected due for release later in 

2006 [not available as of end January, 2007];

 Stakeholders urge WorkSafeBC not to proceed until this study becomes 

available;

 There is no biologically plausible link between formaldehyde exposure and 

leukemia;

o Formaldehyde does not act as a systemic carcinogen;

o It is rapidly metabolized within the body and is highly unlikely to be 

transported to the bone marrow, nor has it been demonstrated to be 

―marrow-toxic‖ – a precursor for leukemia induction.

Stakeholders asked WorkSafeBC to consider the findings of the 2004 IRSST 

formaldehyde report. It is a critical review of the literature of sensory irritation effects of 

formaldehyde – the basis of the ACGIH 0.3 ppm Ceiling Limit. The findings of the 

IRSST report are summarized in Appendix B. The employer submission indicates that, 

according to the IRSST, the threshold for sensory irritation (eye) is in the range of 0.75 

to 1.0 ppm, which is far greater than the 0.3 ppm ceiling proposed by WorkSafeBC. The 

evidence indicates that the difference in the prevalence of significant health effects 

would not be expected by reducing the current WorkSafeBC levels to those 

recommended by the ACGIH.

The employer submission also requested WorkSafeBC consider the 1997 Paustenbach 

et al study. Details germane to this paper are summarized in Appendix B.

The employer submission requests that WorkSafeBC consider the Chemical Industry 

Institute of Toxicology (―CIIT‖) model for carcinogenicity which has been adopted by 

several national and international standard-setting bodies including Health Canada / 

Environment Canada, the German MAK Commission, Environmental Protection Agency, 

Australia‘s Department of Health and Aging (NICNAS), the OECD, the WHO (CICAD) 

and the Dutch Expert Committee (DECOS). The employer submission pointed out that 

IARC did not reference the CIIT model in their recommendations for carcinogenicity for 
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 25 of 69

formaldehyde. The employers also point to the fact that the MAK Commission, NICNAS, 

WHO-CICAD, DECOS and others conclude that formaldehyde exposure poses a 

carcinogenic effect under conditions that both induce toxicity and cause sustained 

regenerative proliferation (i.e., damage in the DNA replication process following severe 

tissue damage). The 1999 CIIT study is reviewed in Appendix B.

c) Economic Issues

Employer representatives maintain that in order for this industry to remain competitive 

both in and outside of Canada, the exposure limit for formaldehyde should reflect that of 

other jurisdictions. In particular, since Canada's primary trading partner is the US, the 

exposure limit should not be lower than that of the Occupational Safety and Health 

Agency (―OHSA‖). Their primary concerns with respect to economic impacts are that if 

the exposure limit is lowered too much, there is the potential for marked disparity in 

compliance and manufacturing costs between BC and its competitors, and the industry 

in BC will, as a result, become less competitive.

Their submission states that 14,884 employees are directly employed in formaldehyde 

monomer, polymer and downstream facilities (primarily the wood products industry) in 

BC, equivalent to over $540 million in wages. When direct, indirect and induced

economic contribution of formaldehyde in BC is tallied, this rises to 80,164 jobs and 

C$2.9 billion in wages with purchases of C$1.7 billion and sales in excess of C$3.9 

billion.

The employer submission claims that consumers in the US and Canada would have to 

spend an additional $17 billion per year if formaldehyde-based products were replaced 

by substitute materials. Substitution is, in many cases, not practical due to increased 

energy requirements, manufacturing safety issues, poor performance, and costs of 

alternate materials.

In another report provided by the employers – a report prepared by the Composite Panel 

Association – it is shown that the wood paneling industry in BC employs 4,419 

employees directly (as of November 2005). They state that the panel board plants which 

are at risk are located in rural BC, in communities such as Grand Forks, Quesnel, and 

Smithers. These plants provide the base for economic activities in these areas and 

provide a much needed outlet for sawmill residues that were previously directed to 

beehive burners creating an environmental concern and wasting a valuable resource. 

In a report received in the 1990‘s by WorkSafeBC from the Canadian Particle Board 

Association, it was estimated that the capital cost of complying in 1993 with an proposed 

Ceiling Limit of 0.3 ppm would be in the order of C$676,000 per plant, with additional 

operating costs of C$335,000 per year (per plant) in BC. It was stated at the time that 

the additional annual operating costs would largely be the result of higher energy costs 

associated with heating the additional air exhausted by the enhanced ventilation 

systems. 

The employers suggest that achievability may be possible in plywood plants but is 

unlikely in particleboard plants and, correspondingly, anticipate that the cost of 

compliance would be higher for the particleboard industry than for the oriented strand 

board and plywood industries. They also suggest (based on OSHA estimates) that the 
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 26 of 69

greatest impact may be felt by the furniture industry because it uses particleboard as a 

raw material.

d) Technical Issues

Concerns have also been raised regarding the technical feasibility of monitoring 

exposure to and demonstrating compliance with such low levels of formaldehyde. It was 

suggested that uncertainty about the accuracy and precision of monitoring data would 

pose problems from the standpoint of both compliance monitoring and enforcement.

Workplace Site Visit

Occupational hygienists from WorkSafeBC visited a panel / fibre board plant in order to 

assess the feasibility of implementing a lower TLV for formaldehyde. As noted by the 

employer group at the September 30th, 2005 meeting with WorkSafeBC staff, a particle 

or fibre board plant is likely to be the most challenged in meeting the proposed Ceiling 

Limit of 0.3 ppm. 

Issues identified During the Site Visit:

 Urea-formaldehyde resin is used in large quantities in making medium density 

fibre board;

 The resin component is 10% by weight of a typical board or panel; the balance is 

wood fiber obtained from waste wood supplies (sawdust) from sawmills;

 Formaldehyde is released to the air in the plant at a number of locations along 

the process line; the initial mixing area, the panel press section, fabrication 

section (panels are cut into various sizes and sanded), and packaging / shipping 

areas;

 Engineering controls are used throughout the plant primarily through the use of 

ventilation, including wet scrubbing systems;

 Ventilated air exhausted from the building exhaust is matched with an equal 

amount of heated make-up air provided to the plant; heat is supplied via natural 

gas;

 Other engineering controls include enclosed control rooms and laboratory; these 

are positively pressurized via dedicated HVAC systems;

 Staff spend most of their shift in these enclosed environments but enter the plant 

to take samples, oversee the process, carry out routine maintenance and similar 

job duties;

 Worker exposures are routinely measured by onsite environmental / occupational 

hygiene staff using a calibrated electronic ―formaldemeter‖ and other sampling 

devices;

 Periodically, consultants will conduct worker exposure surveys;

 Exposure results are posted on staff bulletin boards and discussed at joint OH&S 

committee meetings; 

 Sampling results indicate the following levels for the period January to June 2006 

(based on 7 to 14 readings per month at each location; range indicated over the 

6 month period):

o Laboratory: ranged from 0.06 – 0.27 ppm;

o Control room: 0.07 – 0.16 ppm;

o Press infeed area: 0.23 – 0.30 ppm;
Attachment 1

Appendix A – Stakeholder Consultation and Feedback

July 2009 – OEL for formaldehyde Policy and Research Division Page 27 of 69

o Press outfeed area: 0.32 – 1.19 ppm;

o Mezzanine: 0.23 – 0.35 ppm;

o Catwalk over press: 0.39 – 0.63 ppm;

o Sander station: 0.05 – 0.12 ppm;

o Packaging station: 0.04 – 0.11 ppm; and

o Maintenance shops: 0.03 – 0.06 ppm.

 Few workers work for a full shift in the open plant; hence their time spent in the 

open plant are conservatively estimated to be about 1⁄4 of a full shift or less, 

depending on the job tasks;

 Practically, this means an 8-hour exposure well under 0.3 ppm on a time 

weighted basis; 

 The Ceiling Limit values of 1.0 ppm can be exceeded when a worker is located in 

a potentially high level area such as the press outfeed; 

 Workers who are required to work for longer periods in the plant are provided

with the appropriate respiratory protection which is assigned based on the 

protocols established by the plant‘s respiratory protection program;

 This plant would consistently be in non-compliance if a Ceiling Limit of 0.3 ppm 

with no 8-hour TWA is enforced. 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 28 of 69

This appendix details information on the proposed OELs by reference organizations 

such as the ACGIH, the German MAK Commission, and the UK WATCH13 Committee 

among others. 

Cancer Classification of Formaldehyde by Various Jurisdictions

Part 5 of the Occupational and Safety Regulation (OHSR) recognized the classification 

system for carcinogens based on the classification systems of the ACGIH and the IARC, 

both reference organizations. Other jurisdictions have adopted classification systems

based on the recommendations by reference organizations other than the ACGIH or 

IARC. One of the most noteworthy is the classification system of the Scientific 

Committee on Occupational Exposure Limits (―SCOEL‖). SCOEL‘s recommendations 

on the carcinogen classification have been adopted by the regulatory agencies of the EU 

countries. Germany based its classification system on that of the MAK Commission and 

other national research organizations such as the German Federal Institute for Risk 

Assessment (Bundesinstitut für Risikobewertoung – ―BfR‖).

14 Table B1 provides an 

overview of the carcinogen classification for formaldehyde by these reference 

organizations. 

Table B1. Current Classifications of the Carcinogenic Status for Formaldehyde

Reference 

Organization

Classification

for 

Formaldehyde

Description

ACGIH A2 Suspected human carcinogen – limited evidence of 

carcinogenicity in humans and sufficient evidence of 

carcinogenicity in experimental animals with relevance to 

humans in quality but are conflicting or insufficient to 

classify the substance as a confirmed human carcinogen. 

IARC 1 Carcinogenic to man based on sufficient evidence in 

humans and in experimental animals. Sufficient evidence 

that formaldehyde causes nasopharyngeal cancer, strong 

but not sufficient evidence of leukemia, and limited 

evidence of sinonasal cancer.

European Union 

– SCOEL

3 Concern for man owing to possible carcinogenic effects 

but the available information is not adequate for making a 

satisfactory assessment. There is some evidence from 

appropriate animal studies but this is insufficient to place 

the substance in Category 2 (suspected human 

carcinogen). 

 

13 Working Group on Action to Control Chemicals Committee, a subcommittee of the Advisory Committee 

on Toxic Substances of the UK Health & Safety Executive.

14 Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung) – Germany.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 29 of 69

Reference 

Organization

Classification

for 

Formaldehyde

Description

Dutch -

DECOS15

3 As per SCOEL

German MAK 

Commission16

4 Genotoxicity plays no or at most a minor part. No 

significant contribution to human cancer is expected 

provided the MAK value is observed. 

United Kingdom 

Health & Safety 

Executive

R40

(SCOEL ―3‖)

Limited evidence of a carcinogenic effect in humans.

Similar to SCOEL.

Australia 

NICNAS17

2 Produces tumours in animals – specifically nasal tumours 

at high concentrations.

OEL Reference Organizations – Exposure Limits for Formaldehyde

ACGIH

ACGIH proposed a Ceiling Limit of 0.3 ppm for formaldehyde as far back as 1989 (a 

―Notice of Intended Change‖ substance). The posted limits at the time were a TLV TWA 

of 1.0 ppm and a TLV STEL of 2.0 ppm. In 1992, ACGIH adopted the 0.3 ppm TLV

Ceiling Limit. ACGIH has listed formaldehyde as a ―suspected human carcinogen‖ (A2) 

since 1982. The basis for recommending a ceiling limit is outlined in the 2001 TLV 

Documentation©, and can be summarized, in part, as follows:

“There is a substantial population, comprising up to 20% of the population, for whom airborne 

formaldehyde at concentrations on the order of 0.25 to 0.5 ppm is troublesome. Despite the 

intent of the TLV recommendations to protect most workers, it is believed that the recommended 

formaldehyde 0.3 ppm ceiling TLV will not protect that portion of the workforce reported to be 

responsive to low ambient concentrations of this chemical.

While the epidemiologic studies and case reports do not confirm that occupational exposure to 

formaldehyde is carcinogenic for human beings, several groups have reported that occupational 

formaldehyde exposure may be a factor in the potentiation or predisposition of upper respiratory 

tract cancer when a worker is also exposed to other known or suspected occupational 

carcinogens. Nevertheless, interpretation of the biologically based animal cancer risk 

assessment data18 indicates that the oncogenic potential of formaldehyde is a threshold 

phenomenon and that prevention of upper respiratory tract irritation and the associated 

regenerative hyperplasia should eliminate, for all practical purposes, any excess cancer risk 

posed by occupational formaldehyde exposure alone.

 

15 Dutch Expert Committee on Occupational Standards.

16 Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, a 

reference organization of the German Research Foundation (FDR), Germany.

17 National Industrial Chemicals Notification and Assessment Scheme.

18 CIIT study.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 30 of 69

ACGIH holds to the opinion that TLVs based on physical irritation should be considered no less 

binding than those based on physical impairment. There is increasing evidence that physical 

irritation may initiate, promote, or accelerate physical impairment through interaction with other 

chemical or biological agents. Inasmuch as formaldehyde is associated with rapid onset of 

irritation, a ceiling designation is deemed appropriate for this chemical.

The recommended TLV–Ceiling of 0.3 ppm for workplace air formaldehyde is based on evidence 

of irritation from reports of occupational exposure to formaldehyde as well as human 

formaldehyde exposures in other settings. This recommended TLV may not eliminate all worker 

complaints of sensory irritation associated with exposure to this chemical. However, ACGIH 

believes that the 0.3 ppm ceiling value should result in a significant reduction of complaints 

currently associated with exposure to formaldehyde. The A2, Suspected Human Carcinogen, 

notation, based on cancer in experimental animals and where the epidemiologic studies are 

conflicting or insufficient to confirm an increased risk of cancer in workers, is considered 

appropriate for this chemical.

In light of the numerous reports of allergic reaction or sensitization associated with exposure to 

formaldehyde and products containing formaldehyde, the sensitizer notation (SEN) is 

recommended. Individuals who may already be sensitized or otherwise unusually responsive to 

formaldehyde may not be adequately protected from adverse health effects caused by 

formaldehyde exposures at or below the recommended TLV”.

As noted, the ACGIH based its decision on adopting its current TLV recommendation on 

experimental and epidemiological evidence up to and included data published no later 

than the mid-90s. Many of the studies – including studies by the National Cancer 

Institute and those contemporary at the time (i.e., published prior to the mid-90s) on 

which the current ACGIH Ceiling Limit of 0.3 ppm adopted TLV is based – have since 

received critical re-evaluations. Much new information has come to light since the mid90s. The MAK Commission, responsible for recommending exposure limits in Germany, 

has completed recent reviews (published 2002, 2006), as discussed in Appendix B. 

Other evaluations have been completed including a 2004 review by the IRSST19 in 

Quebec, DECOS20 in 2003, DECOS/NEG21 in 2003, WHO-IPCS22 in 2002, Environment 

Canada / Health Canada in 2001, Australia‘s NICNAS23 in 2005, UK‘s WATCH24 

Committee in 2005, Australia‘s EPHC25 in 2003, WHO / CICAD26 and Germany‘s BfR27

in 2006. OSHA issued a ―final Rule‖ on an OEL for formaldehyde in June 1992.

However, no further re-evaluation has been conducted by this US regulatory agency. 

With the exception of OSHA, most regulatory as well as reference agencies have utilized 

the new information, particularly the evidence provided by a pivotal study on the 

 

19 Institute de Reserche Robert Sauvé en Santé et en Sécurité du Travail – Quebec.

20 Dutch Expert Committee on Occupational Standards.

21 Nordic Expert Group – Norway, Sweden and Finland. 

22 International Programme on Chemical Safety – World Health Organization.

23 National Industrial Chemicals Notification and Assessment Scheme. Australia.

24 Advisory Committee on Toxic Substances – Working Group on Action to Control Chemicals, UK Health 

& Safety Commission, England.

25 Environmental Protection & Heritage Council, National Environmental Protection Measures – Australia.

26 Concise International Chemical Assessment Document – World Health Organization / International 

Labour Organization..

27 Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung) – Germany.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 31 of 69

carcinogenic process involving formaldehyde published by the CIIT28 in 1999. This 

study is described in this Appendix.

MAK Commission

The MAK Commission recently reviewed the OEL and carcinogenic status of 

formaldehyde. In its 2002 publication it declared formaldehyde a category 4 carcinogen 

and prescribed an 8-hour TWA of 0.3 ppm with a Ceiling Limit of 1.0 ppm. The MAK 

Commission considered ―that the genotoxicity of formaldehyde plays no or at most a 

minor part in its carcinogenic potential so that no significant contribution to human 

cancer risk is expected‖. Formaldehyde is classified as a carcinogen category 4 of 

Section III of the List of MAK and BAT Values. These OELs and carcinogen 

classification has been adopted in Germany as regulatory values.

The 2006 MAK Commission report makes the following observations:

“Evaluations of the data now available for the carcinogenic effects confirm that the occurrence of 

tumours in the nasal mucosa of rats and mice are the result of chronic proliferative processes 

caused by the cytotoxic effects of formaldehyde. The dose-response relationship for all the 

parameters investigated, such as damage to the nasal epithelium, cell proliferation, and tumour

incidence and also the formation of DNA cross-links is very flat for low level exposures and 

become much steeper at higher levels of exposure. As long as the cellular proliferation rate is not 

increased – which requires exposure to concentrations in excess of 2 ppm – the probability that 

DNA-protein crosslinks are transformed into mutations is considered low”. 

In the low dose range, the MAK Commission states formaldehyde plays no or least a 

minor part in its carcinogenic potential so that no significant contribution to human 

cancer risk is expected. This conclusion is supported by the results of a risk assessment 

by CIIT (1999) which, for persons exposed to concentrations of 0.1 ppm at the 

workplace for 40 years, yielded a very low additional risk of cancer for non-smokers of 

1.3 x 10-8. The Commission therefore classified formaldehyde in category 4.

In establishing a MAK for formaldehyde – which also takes the carcinogenic risk into 

account, the avoidance of cellular proliferation is therefore decisive. The cause of cell 

proliferation is the irritative effect of the substance on the upper respiratory tract. The 

report states that for this parameter the data base is insufficient for the establishment of 

a MAK value. However, the database for the irritative effects of formaldehyde on the 

eye – a more sensitive parameter – is sufficient. Based on the Paustenbach’s et al

study (1997) in which practically all workers were protected against eye irritation when 

exposed on a daily basis to a maximum concentrations of 0.3 ppm, the Commission 

established a MAK value of 0.3 ppm (8-hour TWA). Concurrently, the STEL is set at 0.6 

ppm and the Ceiling Limit at 1 ppm. At concentrations greater than 1 ppm, irritative 

effects are to be expected.

Due to the sensitizing effects on the skin, the MAK Commission designated 

formaldehyde as a sensitizer – “Sh”.

 

28 Chemical Industry Institute of Toxicology – USA.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 32 of 69

The Commission also classified formaldehyde as a germ cell category 5 mutagen, and 

reported that in experimental exposures – even at high exposure levels – the equilibrium 

concentration maintained in the blood by endogenous formaldehyde (i.e., metabolically 

produced by the body) was not found to be increased. Due to the rapid metabolism it is 

also unlikely that even moderate exposure levels can increase the systemically available 

concentration noticeably. The Commission concluded that given observance to a MAK 

value of 0.3 ppm, exposure to airborne formaldehyde is not expected to make a 

noticeable contribution to the genetic risk for man. 

WATCH Committee – a Health & Safety Executive (HSE) Working Group, United 

Kingdom

The WATCH Committee’s overall interpretation of the data from the post-2000 studies 

(which includes review by Hauptmann et al (2004), Marsh et al (2002)) is that they justify 

increased concern for the carcinogenic potential of formaldehyde in humans – especially 

in relation to nasopharyngeal cancer – but that it falls short of providing conclusive 

evidence that formaldehyde exposure has caused nasopharyngeal cancer. There are 

inconsistencies in the findings of the studies which lack a clear explanation. Similarly, 

the Committee reports that the study by Coggon et al (2003) – in a British cohort study of 

chemical industry workers – provided no convincing evidence for an association 

between formaldehyde exposure and cancer in humans. The Committee also found the 

US garment worker cohort study by Pinkerton et al (2004) unconvincing. They found it 

essentially uninformative about the possible association between the substance and 

nasopharyngeal cancer. 

In relation to the apparent association seen in some studies between formaldehyde 

exposure and leukemia, based on recent reviews of the evidence,

29 and also considered 

biological plausibility, the WATCH Committee considers that there is no basis for any 

concern for leukemia associated with formaldehyde exposure.

The Committee considers formaldehyde a genotoxic carcinogen for which a threshold 

can be determined. No OELs appear to have been recommended for formaldehyde by 

this Committee at this time. 

The Committee recognizes that some authorities advocate approaches for deriving 

exposure standards for ―non-threshold‖ genotoxic carcinogens based on mathematical 

modelling of animal carcinogenicity data to predict exposure levels associated with a 

predetermined level of risk in humans (e.g. excess lifetime risk of developing cancer of 

10-5or 10-6). These are the traditional linear extrapolation methods in deriving thresholds 

for carcinogens – methods used by the US Environmental Protection Agency (“USEPA”) and other agencies until the late 1990s at which time other methodologies 

became apparent such as those developed by the CIIT (1999). There are also ―modelfree‖ linear extrapolation approaches, but both methods involve extensive extrapolation 

below the observed range of data and both methods rest on the assumption of low dose 

linearity. Low dose linearity does not appear to apply to formaldehyde. The Committee 

identified a number of concerns related to these methods that are elaborated below: 

 

29 Including: Collins and Lineker (2004); Heck and Casanova (2004), Cole and Axten (2004); Marsh and 

Youk (2004).
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 33 of 69

 These methods all rely on an assumption of low-dose linearity but at low 

exposures this assumption may not be correct. DNA repair mechanisms may 

lead to a sub-linear dose response at lower doses leading to overestimates of 

risk. 

 The risk estimates derived by mathematical modelling or linear extrapolation lie 

far below the observed experimental range of data and can never be validated by 

empirical observation (to validate a lifetime increased risk of 10-5or 10-6 would 

require far more than the 50 animals per sex per dose group used in standard 

carcinogenicity bioassays). 

 These approaches do not adequately convey the uncertainties involved and so 

imply a level of precision that cannot be justified. A spurious impression of 

scientific accuracy is thereby conveyed. 

 The usual design of rodent carcinogenicity studies (low, medium and high dose 

groups of 50 per sex) cannot distinguish between the various mathematical 

models available in terms of identifying a model that provides the best fit to the 

data. 

 Although the various models can be shown to fit the observed data equally well, 

these models can lead to risk estimates at low doses that vary over several 

orders of magnitude, and there is no way of knowing which model, if any, leads 

to a true approximation of risk.

The PRD is not aware of any OELs that have been recommended for formaldehyde by

the WATCH Committee at this time.

NOTE: The US-EPA, Health Canada and other authorities either have adopted or are 

considering adopting the multi-model biological model developed by the CIIT in lieu of 

the no-threshold model which assumes that cancer risk is linear to zero. There is no 

indication that IARC has considering the biological model.

German Federal Institute for Risk Assessment (BfR) / European Union Scientific 

Committee for the Occupational Exposure Limits to Chemical Agents (SCOEL)

Both SCOEL and the BfR each issued review reports on formaldehyde in 2006 – SCOEL 

issued provisional OELs for formaldehyde. The proposed draft is currently out for 

consultation within Europe. The BfR report focuses more on public health and safety. 

Both organizations had similar findings and will therefore be discussed jointly here. As 

noted by both, in general, epidemiological data cannot be used to support the existence 

of a threshold for genotoxic carcinogenicity. It is not possible to “prove” the existence of 

a threshold due to the statistical limitations. Hence, evidence concerning the existence 

of thresholds will need to be based on mechanistic and experimental rather than 

epidemiological data. 

Both organizations conclude that the carcinogenic mechanism of formaldehyde is based 

on a combination of repeated exposures of cell proliferation due to local tissue irritation 

(cytotoxic effects) of inhaled formaldehyde and also to the formation of DPX (DNAprotein cross-links). Hence the mechanism is a combination of non-genotoxic and 

genotoxic events. Experimental animal evidence indicates a no observed adverse effect 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 34 of 69

level (NOAEL30) for cytotoxicity (non-genotoxic effect) of 2 ppm. However, a clear 

threshold for the induction of DPX (genotoxic effect) could not be identified but the doseresponse data showed a steep increase in DPX formation only occurred at 

concentrations above 2 ppm. Increases in cell proliferation only occurred at 

concentrations above 2.7 ppm. Taking other observations into account it was 

considered that there would be no increase in genotoxic changes at exposures below 

the NOAEL30 for cytotoxicity. 

A clear threshold for respiratory tract cytotoxicity could not be identified in humans, and 

both authorities considered that the NOAEL for sensory irritation in humans could be 

used as a surrogate. A weight of evidence approach to the analysis of human data from 

a number of volunteer studies (Paustenbach et al, 1997) indicated a NOAEL for sensory 

irritation of 0.1 ppm. In the BfR assessment it was noted that the NOAEL for sensory 

irritation was not contraindicated by animal data indicating a threshold for cytotoxicity at 

2 ppm. Overall, 0.1 ppm was proposed by BfR as a ―safe-level‖ for exposure to 

formaldehyde in the general public. This, according to BfR, is in good agreement with 

the MAK value of 0.3 ppm for worker protection in the workplace. This is the regulated 

OEL for Germany.

In their 2006 review, SCOEL stated that a NOAEL of 0.3 ppm for local irritancy is the 

departing point for setting an OEL. At the same time, SCOEL considers that the onset of 

eye irritation is a very sensitive parameter that provides a safety margin to the onset of 

irritation-induced cellular proliferation. Considering the "preferred value approach" in 

setting OELs, an OEL of 0.2 ppm is therefore proposed. Short-term irritation may be 

prevented by an STEL of 0.4 ppm. At these levels, they state that no systemic effect of 

formaldehyde is to be expected. No European regulatory agency has yet adopted these 

values.

WHO / CICAD31 Assessment on Formaldehyde 

The 2003 WHO report is based on the research conducted by Health Canada and 

Environment Canada scientists in conjunction with US-EPA, the CIIT among others. It is 

an omnibus review and considers the toxicological and other harmful properties of 

formaldehyde from both an environmental and human perspective.

They report that based on inhalation studies in laboratory animals, formaldehyde causes 

degenerative non-neoplastic effects in mice and monkeys and nasal tumours in rats. In 

vitro, formaldehyde induced DNA–protein crosslinks, DNA single-strand breaks, 

chromosomal aberrations, sister chromatid exchange, and gene mutations in both 

human and rodent cells. Formaldehyde administered by inhalation or gavage to rats in 

vivo induced chromosomal anomalies in lung cells and micronuclei in the gastrointestinal 

mucosa. 

The results of epidemiological studies in occupationally exposed populations are 

consistent with a pattern of weak positive responses for genotoxicity, with good evidence 

of an effect at site of contact (e.g., micronucleated buccal or nasal mucosal cells). 

 

30 Postscript: erratum noted by Dr. Vyskocil – NOAEL should read LOAEL (lowest-observed-adverseeffect-level)

31 Concise International Chemical Assessment Document – WHO / ILO.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 35 of 69

Evidence for distal (i.e., systemic) effects is ambiguous. Overall, based on studies in 

both animals and humans, formaldehyde is weakly genotoxic, with good evidence of an 

effect at site of contact (i.e., within upper the respiratory tract), but less convincing 

evidence at distal sites (i.e. other body organs and tissues). 

Epidemiological studies taken as a whole do not provide strong evidence for a causal 

association between formaldehyde exposure and human cancer, although the possibility 

of increased risk of respiratory cancers, particularly those of the upper respiratory tract, 

cannot be excluded on the basis of available data. Therefore, based primarily upon data 

derived from laboratory studies, the inhalation of formaldehyde under conditions that 

induce cytotoxicity (generally levels above 2 to 3 ppm) and sustained regenerative 

proliferation is considered to present a carcinogenic hazard to humans.

The concentration response relationships for DNA–protein crosslinking, cytotoxicity, 

proliferative response, and tumours are highly non-linear, with significant increases in all 

end-points being observed at concentrations of 4 ppm and above. This correlates well 

with the concentration at which mucociliary clearance is inhibited and glutathionemediated metabolism saturated (i.e., 4 ppm). Histological changes, increased epithelial 

cell proliferation, and DNA–protein crosslinking are all more closely related to the 

exposure concentration than to the total cumulative intake or dose of formaldehyde. 

While the respective roles of DNA–protein crosslinking, mutation, and cellular 

proliferation in the induction of tumours in the rat nose are not fully delineated, the 

hypothesized mode of carcinogenesis is in keeping with the growing body of evidence 

supporting the biological plausibility that prolonged regenerative cell proliferation can be 

a causal mechanism in chemical carcinogenesis.

Regenerative cell proliferation following formaldehyde-induced cytotoxicity increases the 

number of DNA replications and thus increases the probability of a DNA–protein 

crosslink initiating a DNA replication error, resulting in a mutation. This proposed mode 

of action is consistent with the observed inhibition of DNA replication in the rat nose at 

elevated concentrations and point mutations in the p53 tumour suppressor gene in 

tumours from the noses of rats exposed to formaldehyde as well as increased p53 

expression in pre-neoplastic lesions.

The hypothesized mode of induction of formaldehyde-induced tumours that satisfies 

several criteria for weight of evidence, including consistency, concordance of exposure–

response relationships across intermediate end-points, and biological plausibility and 

coherence of the database, is likely relevant to humans, at least qualitatively. Increased 

cell proliferation and DNA–protein crosslink formation within epithelia of the upper 

respiratory tract have been observed in monkeys exposed to formaldehyde vapour. 

Although not sufficient in itself as a basis for inferring causality, direct evidence on 

histopathological lesions in the nose of humans exposed primarily to formaldehyde in the 

occupational environment is consistent with a qualitatively similar response of the upper 

respiratory tract in humans and experimental animals to formaldehyde. Increased 

human epithelial cell proliferation following in situ exposure to formaldehyde has also 

been observed in a model system in which rat trachea populated with human 

tracheobronchial epithelial cells were xenotransplanted into athymic (thymus gland 

removed) mice.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 36 of 69

Because formaldehyde is highly reactive at the site of contact, dosimetry is of critical 

importance when extrapolating across species that have significantly different 

anatomical features of the nasal and respiratory passages and patterns of flow of 

inhaled air. Since humans as well as other primates are oro-nasal breathers, compared 

with rats, which are obligate nose breathers, effects associated with the inhalation of 

formaldehyde are likely to be observed in a larger area, including deeper parts of the 

respiratory tract. Indeed, in rats exposed to moderate levels of formaldehyde, 

histopathological changes, increased epithelial cell proliferation, and DNA–protein 

crosslink formation are restricted to the nasal cavity; in formaldehyde-exposed monkeys 

(as surrogates for humans), on the other hand, these effects have been observed further 

along within the upper respiratory tract. While the epidemiological studies taken as a 

whole do not provide strong evidence for a causal association between formaldehyde 

exposure and human cancer, the possibility of increased risk of respiratory cancers, 

particularly those of the upper respiratory tract, cannot be excluded on the basis of 

available data.

The CICAD report concludes:

Based primarily upon data derived from laboratory studies, therefore, the inhalation of 

formaldehyde under conditions that induce cytotoxicity and sustained regenerative 

proliferation is considered to present a carcinogenic hazard to humans. CICAD did not 

recommend OEL values for formaldehyde.

Dutch Expert Committee on Occupational Standards (DECOS) and the Nordic 

Expert Group in Conjunction with DECOS

DECOS completed a comprehensive review on formaldehyde published in 2003. 

Concurrently NEG issued a similar review report on the substance with similar findings 

and conclusions. Both DECOS and NEG are research organization charged with the 

review of OELs and recommending OELs for regulatory consideration by the authorities 

in their perspective countries.

DECOS and NEG make similar conclusions to those of WHO / CICAD and CIIT on the 

health effects of formaldehyde. 

In view of the evidence in experimental animals and humans, and a thorough and critical 

appraisal of the available data, DECOS posed a question: 

 Does an exposure limit of 0.12 ppm protect workers against cytotoxicity-induced 

hyper-proliferation of the nasal respiratory epithelium, and consequently also 

against the potential risk of nasal cancer?

Their answer is in the positive, and DECOS considers a health based 8-hour TWA 

occupational exposure level (HBR-OEL) of 0.12 ppm formaldehyde low enough to

protect workers against nasal tissue damage, and as a consequence, also against the 

potential risk of nasal cancer. DECOS states that this conclusion is strongly supported 

by the results of a recently published quantitative cancer risk assessment of airborne 

formaldehyde, using a very sophisticated biologically-based model that predicts for 

occupational exposure (40 years beginning at the age of 18, 8 hours/day, 5 days/week) 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 37 of 69

to 0.1 ppm formaldehyde an increased lifetime risk for cancer of 10-7for smokers and 4.1 

x 10-9for non-smokers (CIIT, 1999), which are regarded as negligibly small risks.

To avoid peak exposures possibly entailing cytotoxicity-induced hyper-proliferation and 

metaplasia of the nasal respiratory epithelium, DECOS recommends for formaldehyde a 

STEL, using data from the review of Paustenbach et al 1997, and others. The review of 

Paustenbach suggested that at a concentration of 1.0 ppm sensory effects might occur. 

The committee concluded that the total body of evidence indicates that 0.42 ppm is an 

exposure level which is low enough to avoid significant sensory irritation from short term 

exposures and thus, more importantly, also will be low enough to avoid nasal cytotoxicity 

from such short exposures. In conclusion, the committee considers a factor of 2 

sufficient for the extrapolation from lowest observed adverse effect level (―LOAEL‖) to 

the no-adverse-effect-level (―NAEL‖). Therefore, DECOS recommends a STEL of 

0.42 ppm. 

Conclusion: DECOS recommends a health-based occupational exposure limit of 0.12

ppm formaldehyde, as an 8 hour time-weighted average, and a short term exposure

limit, 15 minutes TWA, of 0.42 ppm. Neither Holland nor the Nordic countries, including 

Sweden, Norway or Finland have adopted these OELs for regulatory purposes. 

National Industrial Chemical Notification Assessment Scheme (NICNAS) of the 

Australian Department of Health and Aging

NICNAS, a reference agency for the Australian government, released its draft 

Formaldehyde Priority Existing Chemical Assessment Report in 2005 for stakeholder 

and public consultation. It released a response report in November of that year. While 

their consultation period is still active, NICNAS has made the following statements that 

are germane to this review:

 In order to classify a chemical as a category 1 carcinogen, there must be 

sufficient human evidence to establish a causal association between exposure to 

the chemical and cancer.

 NICNAS concluded that the strength of the epidemiology data was not sufficient 

to establish a casual relationship between formaldehyde exposure and cancer in 

humans. For nasopharyngeal cancers there are several epidemiological studies 

that show an increased risk, whereas other studies do not. 

 Of the three recently published cohorts, only the NCI study (Hauptmann et al, 

2004) showed an increased risk of nasopharyngeal cancers and this was 

associated with increased average exposure intensity and highest peak 

exposures. 

 Marsh and Youk (2005) revaluated the data of the NCI study and concluded that 

there was little support for NCI‘s suggestion of a causal relationship between 

formaldehyde exposure and mortality from nasopharyngeal cancer. 

 Coggon et al (2003) and Pinkerton et al (2004) did not observe an increased risk 

for nasopharyngeal cancers. 

 There are also concerns for an increased risk for formaldehyde-induced myeloid 

leukemia. However, the available data are not considered sufficient to establish 

an association and there is currently no postulated mode of action to support 

such an effect. 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 38 of 69

 Therefore, it is considered that there is currently insufficient evidence to establish 

a causal association between human exposure and the development of cancer 

on the basis of epidemiological data.

 While they acknowledge the fact that it is difficult to identify a definitive no 

observed effect level (―NOEL‖) for sensory irritation, they have taken a cautionary 

approach and selected 0.5 ppm as the lowest observed effect level (―LOEL‖) and 

added appropriate uncertainty factors to establish the recommended 

occupational exposure standard (8-hour TWA) as 0.3 ppm. This value provides 

a level that will not only manage the risk of sensory irritation, but also manage 

the cancer risk.

 NICNAS considers the clonal growth model developed by CIIT and further 

developed by Conolly et al, 2004 the best estimate of cancer risk for 

formaldehyde. 

 The clonal growth model predicts that for 40-year occupational exposure to 0.3 

ppm formaldehyde (the NICNAS recommended occupational exposure standard)

the estimated additional risk for respiratory tract cancers is approximately 2 in 10 

million.

 While at 1 ppm (the current Australian occupational exposure standard) the 

estimated additional risk is approximately 50 in a million. Similarly for public 

exposure, at the recommended indoor air guidance value (80 ppb or 0.08 ppm), 

the estimated additional risk is approximately 3 in 10 million.

 Although NICNAS considers the risk of cancer to be low, they do not consider 

that the strength of data nor the degree of certainty is sufficient to conclude that 

the cancer risk is negligible.

 Based on the information, NICNAS is showing support for an 8-hour TWA of 0.3 

ppm and a 0.6 ppm STEL and that formaldehyde be classified as a category 2 

carcinogen (producing tumours in animals – specifically nasal tumours at high 

concentrations).

 In the draft, NICNAS makes the following statement:

o ―In order to protect the majority of workers from sensory irritation, the 

recommended exposure standard should be a concentration that is a 

lower than the LOEL identified. As this is a reversible effect and effects 

are generally mild at 0.5 ppm, the standard should be slightly lower than 

the LOEL. For these reasons the recommended exposure standard is 0.3 

ppm TWA and 0.6 ppm STEL. At this level, the nasal cancer risk can be 

also managed. Furthermore the recommended exposure standards are 

consistent with best practice overseas and from industry information 

submitted for this report appear technically achievable in most Australian 

workplaces.‖

This statement is similar to that of the MAK Commission. They conclude by stating that 

there is an ongoing follow-up for the NCI study, which is likely to be published in 2007. 

NICNAS believes it is important to review the NCI data and any other significant 

epidemiological date, when they become available. They propose that the following text

be added to section 19, Secondary Notification:

―NICNAS should re-evaluate the cancer hazard classification if and when any 

new significant epidemiology data becomes available.‖
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 39 of 69

Conclusion: NICNAS recommends an 8-hour TWA OEL of 0.3 ppm and a STEL of 0.6 

ppm and classify formaldehyde as a category 2 carcinogen. This is a similar conclusion 

to that of the MAK Commission. 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 40 of 69

IRSST – Quebec

This study, commissioned by the IRSST, was completed by research scientists at the 

Université de Montréal. It was initially published in 2004 in French with an English 

version issued January 2006. 

Overall, the project aimed to evaluate the impact of lowering the current Quebec 

Commission of Health and Safety permissible exposure value – Ceiling Limit for 

formaldehyde, which is currently set at 2 ppm; they are considering setting it to 1.0, 0.75 

or 0.3 ppm. The objective of this study was to estimate as precisely as possible the 

dose-response relationship between exposure to formaldehyde and the appearance of 

health-related effects in workers.

A series of criteria was established in order to select and classify the parameters based 

on their scientific qualities; statistical analyses were conducted in order to establish this 

exposure-response relationship for the earliest effects after an acute exposure, i.e., the 

irritating effects. The determination of the risk of cancer after a long-term exposure was 

obtained by considering dose-response relationships provided by different agencies and 

by applying them to the Quebec data.

The IRSST notes the following:

 The study data systematically defines the dose-response relationship, allowing 

calculation of responses attributable to formaldehyde according to the site of the 

irritative effect (eye, nose, throat);

 They conclude that for concentrations less than 0.75 ppm, the frequency of 

irritation in workers exposed to formaldehyde was about the same one observed 

in individuals without occupational exposure, indicating that appearance of 

irritation at such concentrations can hardly be associated with occupational 

exposure to the substance; 

 Among the workers exposed to a formaldehyde concentration between 0.75 and 

<1.0 ppm, 6.3% are likely to experience moderate eye irritations; 

 None would be likely to experience severe eye irritations and 1.6% would have 

moderate nose and throat irritations;

 As shown in Figure B2,

o Between 0 to less than 0.75 ppm no irritating effects are noted;

o Between 1 ppm and less than 2.0 ppm, 10.1% experienced moderate eye 

irritation, 0.8% severe eye irritation, 4.5% moderate nose irritation and 4.6 

% moderate throat irritation;

o Above 2 ppm a corresponding increase in responses are noted.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 41 of 69

Figure B2: Average theoretical percentage of the exposed population that is likely to

experience irritating eye, nose or throat effects attributable exclusively to formaldehyde 

according to the severity of the effect for a given class of exposure (adapted from IRSST 

2006).

 From a compensation claims perspective, IRSST notes that complaints due to 

formaldehyde exposure reported to the CSST (Quebec Commission of Health 

and Occupational Safety) are rather rare. As for cases of protective 

reassignment, 11 cases were reported in four years among six CAEQ (Quebec 

Economic Activities Classification) codes, four business sectors and nine 

different occupations. No cases of occupational illness that were attributable to 

formaldehyde were reported in the same period.

 On the basis of the epidemiological data in literature and the position of several 

agencies of toxicological risk evaluation, there is limited evidence of 

formaldehyde‘s carcinogenic effects on humans.

 If one refers to the exposure data of the IRSST, the probability of frequent 

exposure to the ceiling values indicated in the matrices is low. The duration of 

the ceiling values in these matrices is about one minute each. In other words, a 

worker exposed to an average value for eight hours that was low, cannot have 

been exposed to ceiling values of a relatively high frequency and intensity. 

Otherwise, the average would be higher.

 ACGIH also evaluated the health impact of formaldehyde exposure. The majority 

of the studies selected and analyzed for this evaluation were the same as the 

ones the IRSST selected. The conclusions of these studies are therefore the 

same between the ACGIH analysis and this analysis. However, ACGIH went 

one step further than scientific evaluation. They proposed a recommendation of 

an acceptable Ceiling Limit of 0.3 ppm based on their own interpretation of the 

data. This recommendation is based on the desire to avoid a maximum of 

irritations in workers. This includes even the mildest irritation, given that some 

studies showed that the most sensitive people complained of irritation at 

concentrations as low as 0.3 ppm, without taking into account the degree of 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 42 of 69

severity of effects (only the presence or absence of effect is taken into account, 

without giving more weight to more severe effects), or the population response at 

background level (in controlled studies, an equal or a higher incidence was 

observed at 0 ppm than at 0.3 ppm.). In addition, the quality difference between 

the controlled studies and the studies involving workers was not taken into 

account in the process of risk evaluation. The ACGIH therefore recommends a 

ceiling value of 0.3 ppm and specifies ―concentrations should be reduced to the 

lowest levels detectable by the measuring equipment.‖

 IRSST‘s analysis of the selected epidemiological studies demonstrates that some 

studies showed an association between formaldehyde exposure and cancer, 

while other studies did not show such a relationship. Nevertheless, all these 

epidemiological studies have methodological limitations that reduce the 

confidence level of the results. These limitations are mainly lack of power, the 

presence of confounding factors, the fact that an effect is observed in the least 

exposed groups and but no effect in the most exposed groups, the lack of 

measurement of exposure level in numerous cases, or sporadic measurements. 

Consequently, there is limited proof of the carcinogenic potential of formaldehyde 

in epidemiological studies but it is not possible, based on epidemiological 

studies, to establish a dose-response relationship between formaldehyde 

exposure and the onset of cancer.

 Because of the inconsistencies among the results of the epidemiology studies 

regarding the association and strength of association, frequent methodological 

limitations such as lack of power and a limited determination of actual exposure, 

the inability of cohort studies to observe an increased risk because the studied 

types of cancer are rare, and the lack of a dose-response relationship that 

increases with increasing doses, the evidence for a causal association is very 

limited, although it cannot be entirely excluded. In animals, the proof of a causal 

relationship appeared sufficient to us, but the increase in cancer was observed 

only at high concentrations. The cellular alterations in the tissues of the 

respiratory tract make this relationship plausible. It must be remembered, 

however, that the concentrations at which an excess of cancer was observed in 

animals also induce severe irritation. These factors can contribute to a 

significant increase in cancer risk through an epigenetic or promoter mechanism. 

 These observations suggest that at concentrations at which irritation is low or 

non-existent, the cancer risk, if any, increases more slowly with the increase in 

dose than when irritation is severe and chronically present. At the concentrations 

at which cancer was observed in animals (5.6 ppm and higher), no worker could 

remain in his work environment, because irritation to the respiratory tract and 

eyes would be completely intolerable.

 As far as the estimations of excess risk are concerned, based on high-to-low 

dose mathematical extrapolation models, the CIIT model appears more 

appropriate than the US EPA model in estimating the workers‘ risk. This is 

especially true since the estimates of this model for low doses approach the 

levels of excess risk observed in the epidemiological studies where a positive 

statistical association was observed.

Conclusion: The IRSST concludes that for concentrations less than 0.75 ppm, the 

frequency of irritation in workers exposed to formaldehyde was about the same one 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 43 of 69

observed in individuals without occupational exposure. There is no indication that the 

IRSST has made recommendations regarding OELs. 

Summary of Recommendations of OELs for Formaldehyde by Reference 

Organizations.

Table B3 summarizes recommendations for occupational exposure limits from the 

ACGIH and other reference agencies from Europe, the United Kingdom, Quebec and 

Australia. The MAK Commission recommendations (adopted as regulated OELs in 

Germany) are identical with the recommendations by NICNAS with the exception that 

the Australian organization did not recommend a Ceiling Limit value. The MAK 

recommendation is identical to the currently prescribed OELs in British Columbia - in 

place since 1998. The WATCH Committee has not recommended OELs at this point; 

nor has the IRSST.

Table B3: OELs recommended by reference organizations

Reference 

Organization

8-h TWA OEL

ppm

STEL OEL 

ppm

Ceiling Limit 

OEL ppm

ACGIH - USA - - 0.3

DECOS - Holland 0.12 0.42 -

MAK Commission32

- Germany

0.3 0.6 1

SCOEL- EU 0.2 0.4 -

NICNAS - Australia 0.3 0.6 -

WATCH - UK - - -

IRSST- Quebec - - -

Non-Reference Organizations

For the purposes of reviewing the health effects of formaldehyde and considerations for 

setting an appropriately protective occupational exposure limits for the substance, two 

critical studies referenced by WATCH, DECOS, NEG, and others reviewed above, are 

brought into this discussion.

Chemical Institute of Toxicology 1997 report:

Derivation of the dose–response model and selection of various parameters as it relates 

to formaldehyde are presented in this 336 page omnibus study undertaken by the CIIT in 

conjunction with scientists from the US EPA, Health Canada, University of Pittsburgh 

 

32 Adopted by the German regulatory agency - Deutsche Forschungemeinschaft (DFG).
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 44 of 69

and others. Only a brief summary is provided here. Basically, the CIIT model (which 

incorporates various toxicological, mechanistic and dosimetric parameters) has 

superseded earlier models such as the ―no threshold‖ model that assumes that cancer 

risk is linear to zero as used by the US EPA, the NCI and most regulatory agencies 

since the 1970s. This is despite the fact that it has been recognized that tumour dose–

response relationship is highly non-linear. Since then, a great deal of research has 

focused on better characterizing the factors that play a role in the etiology of nasal 

tumours so that a better understanding of the likely shape of the dose response curve in 

the low dose region can be determined. This includes additional research on the 

induction, persistence, and repair of DNA-protein crosslinks (―DPX‖) at low and high 

concentrations and for acute and longer-term exposures. It also includes research on the 

induction of cell proliferation, which is considered to be an essential precursor event to 

the development of cancer in rats and other species, including humans.

The CIIT multi-modal model is considered by many to be a far more powerful and 

precise predictor of cancer risks and greatly minimizes the need for unfounded 

assumptions and uncertainties as in currently used regulatory approaches to 

carcinogens – the ―no threshold‖ model. The CIIT model for formaldehyde predicts a 

risk for cancer a 1,000-fold less than the EPA prediction. 

CIIT‘s clonal growth model is similar to other biologically based, two-stage clonal growth 

models (also known as Moolgavkar – Knudsen – Venzon (MVK) models), incorporating 

information on normal growth, cell cycle time, and cells at risk (in various regions of the 

respiratory tract). In modelling, formaldehyde is assumed to act as a direct mutagen, 

with the effect considered proportional to the estimated tissue concentration of DPX.

The concentration-response curve for DPX formation is linear at low exposure

concentrations and increases in a greater than linear manner at high concentrations, 

similar to those concentrations administered in the rodent carcinogenicity bioassays. 

For cytotoxicity and subsequent regenerative cellular proliferation associated with 

exposure to formaldehyde, the non-linear, disproportionate increase in response at 

higher concentrations is incorporated. Values for parameters related to the effects of 

formaldehyde exposure upon the mutagenic (i.e., DPX formation) and proliferative 

response (i.e., regenerative cell proliferation resulting from formaldehyde-induced 

cytotoxicity) were derived from a two-stage clonal growth model developed for rats, 

which describes the formation of nasal tumours in animals exposed to formaldehyde.

Species-specific dosimetry within various regions of the respiratory tract in laboratory 

animals and humans was also incorporated. Regional dose is a function of the amount 

of formaldehyde delivered by inhaled air and the absorption characteristics of the lining 

within various regions of the respiratory tract. The amount of formaldehyde delivered by 

inhaled air depends upon major airflow patterns, air-phase diffusion, and absorption at 

the air–lining interface. The ―dose‖ (flux) of formaldehyde to cells depends upon the 

amount absorbed at the air-lining interface, mucus/tissue-phase diffusion, chemical 

interactions such as reactions and solubility, and clearance rates. Species differences in

these factors influence the site-specific distribution of lesions.

The F344 rat and rhesus monkey nasal surface for one side of the nose and the nasal 

surface for both sides of the human nose were mapped at high resolution to develop 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 45 of 69

three-dimensional, anatomically accurate computational fluid dynamics (―CFD‖) models 

of rat, primate, and human nasal airflow and inhaled gas uptake. The approximate 

locations of squamous epithelium and the portion of squamous epithelium coated with 

mucus were mapped onto the reconstructed nasal geometry of the CFD models. These 

CFD models provide a means for estimating the amount of inhaled gas reaching any site 

along the nasal passage walls and allow the direct extrapolation of exposures 

associated with tissue damage from animals to humans via regional nasal uptake. 

Although development of the two-stage clonal growth modelling for rats required 

analysis of only the nasal cavity (rats being obligate nose breathers), for humans

carcinogenic risks were based on estimates of formaldehyde dose to regions (i.e., 

regional flux) along the entire respiratory tract.

The human clonal growth modelling (Figure B4) predicts the additional risk of 

formaldehyde-induced cancer within the respiratory tract under various exposure 

scenarios. Two of the parameters in the human clonal growth model – the probability of 

mutation per cell division and the growth advantage for pre-neoplastic cells, both in the 

absence of formaldehyde exposure – were estimated statistically by fitting the model to 

human 5-year age group lung cancer incidence data for non-smokers. The parameter 

representing the time for a malignant cell to expand clonally into a clinically detectable

tumour was set at 3.5 years.

Figure B4: Roadmap (conceptual framework) for the human clonal growth model. 

The figure shows interrelationships of the major components of the dosimetry and clonal 

growth models used to model tumor incidence in humans. The gray boxes indicate 

components of the human program that use data from rats or monkeys for cases where 
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 46 of 69

the equivalent human data were not available. CFD = computational fluid dynamics; 

DPX = DNA-protein cross-linking (from CIIT, 1999 and CICAD, 2002).

Estimates of carcinogenic risks using the human clonal growth model were developed 

for typical environmental exposures (i.e., continuous exposure throughout an 80-year

lifetime to concentrations of formaldehyde ranging from 0.001 to 0.1 ppm). The human 

clonal growth model describes a low-dose, linear carcinogenic response for humans 

exposed to levels of formaldehyde of 0.1 ppm, where cytotoxicity and sustained cellular 

regenerative proliferation do not appear to play a role in tumour induction. Indeed, the 

effect of formaldehyde upon regenerative cellular proliferation did not have a significant 

impact upon the predicted carcinogenic risks at exposures between 0.001 and 0.1 ppm. 

Conclusion: Based on the multi-modal model, CIIT considers that formaldehyde 

exposure poses a carcinogenic effect only under conditions that both induce toxicity and 

cause sustained regenerative proliferation (damage in the DNA replication process). 

NOTE: The CIIT model for carcinogenicity has been widely used by other agencies and 

organizations (e.g., Environment Canada / Health Canada 2002, CICAD 2002, NICNAS 

2005) as a more reliable estimate of cancer risk for formaldehyde exposures than the 

standard default assumptions used by the EPA and others in the past.

Paustenbach et al 1997 study:

This study presents the findings of a panel of scientists to identify an occupational 

exposure limit for formaldehyde that would prevent irritation. Upon review of 150 papers 

published on irritant effects of formaldehyde, the panel felt that 18 were pertinent in 

developing an exposure limit based on irritation. They concluded that, for most persons, 

the eye is the most sensitive indicator of irritation. They report that moderate to severe 

eye, nose, and throat irritation does not occur until airborne concentrations exceed 2 to 3 

ppm. They also opined that at levels up to 0.3 ppm there is no increase in eye irritation 

above background. Nevertheless, studies of exposures ranging from 0.3 ppm to 

0.5 ppm showed tremendous variability with reported irritation responses ranging from 

0 to 90%. 

The weight of evidence concentration-response curve considered by the panel showed 

that 5 to 25% of workers could report eye irritation in the 0.5 to 1.0 ppm range following 

1⁄4 to 6 hours of exposure and that eye irritation does not become significant until levels 

of formaldehyde reach at least 1 ppm. The panel concluded that at a level of 1 ppm 

would avoid eye irritation in at least 75% and up to 95% of exposed workers.

The panel subsequently put forth a position that they felt that the ACGIH TLV of 0.3 ppm 

(ceiling) was unnecessarily restrictive and they recommended an exposure limit of 0.3 

ppm (8-hour time-weighted average) with a ceiling limit of 1 ppm. They also put forward 

the position that any occupational or environmental guideline for formaldehyde should be 

based primarily on controlled experimental studies in humans since nearly all other 

studies are compromised by the presence of other contaminants.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 47 of 69

Conclusion: A level of 1 ppm avoids eye irritation in at least 75% and up to 95% of 

exposed workers. The panel recommended an 8-hour TWA OEL of 0.3 ppm with a 

ceiling limit of 1 ppm.

Arts et al, 2006 study: 

Following the Paustenbach et al 1997 study, this peer-reviewed article by scientists at 

the Netherlands Organization for Applied Scientific Research (―TNO‖) evaluated the 

adverse health effects of formaldehyde exposure including sensory irritation and the 

potential for tumour development in the upper respiratory tract, comparing animal data 

with subjectively measured sensory irritation thresholds in humans. They also looked at 

benchmark dose analysis (―BMD‖) of sensory irritation – a mathematical model approach 

to fitting experimental data, plotting response against dosage. 

Findings of the study are as follows:

 The absolute odour threshold for formaldehyde, defined as the concentration at 

which a group of observers can detect the odour in 50% of the presentations, has 

been shown to be between 0.05 and 0.18 ppm.

 Formaldehyde is irritating to the eyes and respiratory tract. Respiratory tract 

irritation on the one hand is a localized patho-physiological response to a 

chemical involving local redness, swelling, pruritis, or pain. 

 On the other hand, respiratory tract irritation and eye irritation can also involve a 

chemosensory effect, i.e. interaction with local nerve endings (nervus trigeminus) 

which is called trigeminal stimulation or sensory irritation.

 Over a broad range of concentrations, the trigeminal nerve stimulation will not 

necessarily lead to cell or tissue damage. In contrast, it will lead to a reduction in 

the breathing frequency aimed to reduce the total amount of inhaled material in 

order to protect the individual.

 For several odorous irritating chemicals, such as formaldehyde, substantial

differences in the lowest concentration found to be irritating to eyes, nose and/or 

throat in humans exist.

 These observations can generally not be explained by differences in method 

sensitivity, inherent variability in biological response, or fluctuations in the 

exposure concentrations. These chemicals usually have a strong odour, and at 

least part of the wide variation in the findings may be ascribed to insufficient 

distinction between olfactory and trigeminal stimulation in several of the studies.

 The response at low formaldehyde levels should therefore be translated into 

perception or awareness rather than an annoying eye or nasal irritating reaction.

 It can, therefore, be concluded that when minimal/mild/slight irritation, which is 

still not annoying, is taken as a cut off level, eye and nasal irritation were found at 

formaldehyde levels of equal to / greater than (≥) 1 and equal to / greater (≥) 2 

ppm, respectively, with the annotation that the threshold level of 1 ppm for eye 

irritation was based on the study by Bender et al. (1983) using pre-selected 

volunteers. Using the same reasoning, the minimal/mild/slight irritation level 

would be equal to / greater than (≥) 3 ppm formaldehyde for throat irritation, 

whereas levels of up to 3 ppm did not result in dyspnea (chest tightness /

discomfort) or cough (Sauder et al., 1986; Kulle et al., 1987; Kulle, 1993).

 A similar conclusion was reached by Paustenbach.
Attachment 1

Appendix B – Formaldehyde OELs and Carcinogen Status According to 

Various Regulatory Jurisdictions and Reference Organizations

July 2009 – OEL for formaldehyde Policy and Research Division Page 48 of 69

 At concentrations below 1 ppm, symptoms disappeared very quickly, underlining 

the non-adversity of the effects at low concentrations.

 Sensory irritation, as perceived by human subjects, can be strongly influenced by 

subjective feelings and interpretations when subjected to substances with strong, 

distinctive odours such as formaldehyde, it is a difficult job to set occupational 

exposure limits for odorous substances.

 Asthmatics do not seem to be more sensitive to formaldehyde than nonasthmatics exposed to concentrations up to 3 ppm.

 The NOEL for respiratory epithelial hyper/metaplasia found in long-term 

inhalation toxicity studies in rats suggests that formaldehyde is carcinogenic only 

at cytotoxic levels, i.e. at levels at which sustained regenerative epithelial 

proliferation is observed (≥6 ppm).

 Therefore, based primarily upon data derived from animal studies, inhalation of 

formaldehyde under conditions that induce cytotoxicity and sustained 

regenerative epithelial proliferation within the respiratory tract is considered to 

represent a carcinogenic hazard to humans. Airborne levels of formaldehyde 

below 1 ppm, therefore, seem low enough to protect workers against nasal tissue 

damage, and consequently, also against the potential risk of nasal cancer.

Table B4: Summary of effect levels of formaldehyde in humans and rats (from Arts 

et al, 2006)

Conclusion: The report by Arts et al indicates that airborne levels of formaldehyde below 

1 ppm appear are low enough to protect workers against nasal tissue damage, and 

consequently, also against the potential risk of nasal cancer
Attachment 1

Appendix C – Chemical Characteristics, Routes of Entry, Biochemical 

Pathways, Chronic and Adverse Health Effects Associated with Exposure 

to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 49 of 69

Sections C1 and C2 summarize information from a number of sources including ASTDR 

1999, ACGIH 2001, IARC 1995, DECOS 2003, NEG / DECOS 2003, ECOTEC 1995, 

CITT 1999, MAK Commission 2002 / 2006, WHO 2003, Health Canada / Environment 

Canada 1999, and SCOEL 2006. Since many of these organizations provide very 

similar information germane to the topics outlined in this appendix, no effort has been 

made to identify and distinguish specific references.

C1: Chemical Characteristics of Formaldehyde:

 Formaldehyde (CAS No. 50-0-0) is a colourless, highly flammable gas;

 Formaldehyde enters the environment from natural sources (including forest 

fires) and from direct human sources, such as automotive and other fuel 

combustion and industrial uses;

 Secondary formation also occurs by the oxidation of natural and anthropogenic 

organic compounds present in air. The highest concentrations measured in the 

environment occur near anthropogenic sources; these are of prime concern for 

the exposure of humans and other biota;

 Formaldehyde does not persist in the environment.

C2: Routes of Entry, Biochemical Pathways, Elimination of Formaldehyde:

Exogenous Formaldehyde (sources external to the body)

 External sources of formaldehyde enter either the body via inhalation of gaseous 

or vaporous formaldehyde or via ingestion of formaldehyde-containing 

substances;

 There is some potential for dermal absorption, but this has not been well 

characterized;

 The substance is rapidly and almost entirely absorbed following exposure by 

both the oral and inhalation routes.

Endogenous Formaldehyde (sources internal to the body)

 Formaldehyde is produced endogenous within the body, a product of normal 

metabolism;

 It is an essential metabolic intermediate present in all cells and is readily 

incorporated into macromolecules via normal metabolic pathways. Endogenous 

sources of formaldehyde include the metabolism of serine, glycine, methionine, 

and choline; it is also produced by the demethylation of N-, 0-, and S-methyl 

compounds;

 Formaldehyde is an essential intermediate in the biosynthesis of purines, 

thymidine, and some amino acids;

 Because formaldehyde is a normal metabolic intermediate, it is not stored in any 

tissue to an appreciable extent;

 Hence, the substance is always present in the body and exists in all organs and 

tissues at quantifiable levels (2 – 3 μg/g range in humans; similar levels in the rat 

and monkey).
Attachment 1

Appendix C – Chemical Characteristics, Routes of Entry, Biochemical 

Pathways, Chronic and Adverse Health Effects Associated with Exposure 

to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 50 of 69

Absorption

 Due to its highly hydrophilic (―water loving‖) nature, inhaled formaldehyde is 

rapidly and almost entirely absorbed in the respiratory tract. In obligate nasal 

breathers (―nose breathing only‖) such as rats, formaldehyde is almost 

completely absorbed in the nasal passages; in monkeys (―oronasal breathers‖), 

absorption occurs primarily in the nasal passages but also to a lesser extent in 

the trachea and proximal regions of the major bronchi;

 The species-specific differences in the actual sites of formaldehyde uptake, and 

hence sites of nasal lesions, are determined by complex interactions among 

nasal anatomy, ventilation, and breathing patterns (e.g., nasal versus oronasal);

 Humans are oronasal breathers, such that there is a greater potential for 

formaldehyde to impact the oropharynx and portions of the lower respiratory 

tract, specifically the tracheobronchial region. The degree to which humans use 

oral versus nasal breathing is generally affected by activity patterns, with a 

greater ventilatory drive requiring increased mouth breathing;

 Following oral administration, absorption of formaldehyde is also rapid. Only 1% 

of the radioactivity from an administered oral dose (7 mg/kg) of C14 labelled 

formaldehyde was excreted in the feces, indicating almost complete absorption.

Distribution within the Body

 Formaldehyde reacts very quickly at the site of contact and is rapidly metabolized 

by enzymes in the target tissue;

 It can also be metabolized by enzymes in erythrocytes (blood cells), so that 

exposure to even high concentrations of atmospheric formaldehyde does not 

result in an increase in blood concentrations;

 In a study with human volunteers who were exposed to 1.9 ppm formaldehyde 

for 40 min, the level of formaldehyde in blood was not increased above preexposure levels. Neither were blood levels elevated in rats exposed to 14.4 ppm 

formaldehyde in another study for 2h duration or monkeys exposed to 6 ppm 

formaldehyde for 6 h/day, 5 days/wk for 4 wk.

Metabolism

 Formaldehyde is efficiently metabolized to formate by all tissues of the body as a 

normal metabolic process. Endogenous and exogenous formaldehyde are 

handled metabolically by the same processes;

 Following inhalation, formaldehyde is rapidly metabolized in the respiratory 

tissues with which it first comes into contact;

 Formaldehyde dehydrogenase is the primary enzyme involved in the metabolism 

of formaldehyde and is widely distributed in all tissues;

 Other enzymes (e.g., nonspecific aldehyde dehydrogenase and catalase) can 

also catalyze the oxidation of formaldehyde but are not specific for formaldehyde;

 The specific pathway for the metabolism of absorbed formaldehyde involves 

reaction with glutathione to form S-hydroxymethyl-glutathione. This 

hemithioacetal is then oxidized by formaldehyde dehydrogenase to form 
Attachment 1

Appendix C – Chemical Characteristics, Routes of Entry, Biochemical 

Pathways, Chronic and Adverse Health Effects Associated with Exposure 

to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 51 of 69

S-formylglutathione, which is subsequently hydrolyzed to release glutathione and 

formate;

 Formate can then enter the one-carbon pool to be utilized in purine synthesis, 

excreted in the urine, or further metabolized to CO2 + H2O to be expelled via the 

respiratory tract.

Excretion

 Formaldehyde is eliminated via two pathways – exhalation via the respiratory 

tract or via renal elimination, as noted above;

 Although there appears to be no human data available, studies on rats exposed 

to C14 labelled formaldehyde indicated that about 62% of the inhaled radioactivity 

was excreted renally (as formic acid) and about 40% exhaled as C14 labelledCO2;

 Neither formaldehyde nor its metabolic derivatives (formate, formic acid) 

accumulate to any significant extent in the body.

The overall metabolism of formaldehyde can be summarized diagrammatically as follows 

(source: DECOS 2003).

C3: Health Effects:

Numerous studies have been conducted to evaluate the health effects associated with 

exposure to formaldehyde. Documented effects include: irritation of the eyes, 

respiratory tract, and skin; allergenic skin sensitization; carcinogenicity and mutagenicity.

Irritation

Formaldehyde's irritant effects have been documented over a wide range of 

concentrations. Irritation of the eyes and upper respiratory tract, specifically the nose 

and throat, and increased upper airway resistance have been observed in some studies 

at concentrations between 0.05 and 25 ppm. In other studies, effects on the lower 

airways and chronic pulmonary obstruction have been reported in the range of 5 to 30 

ppm. More severe effects  including pulmonary edema, inflammation, pneumonia, 
Attachment 1

Appendix C – Chemical Characteristics, Routes of Entry, Biochemical 

Pathways, Chronic and Adverse Health Effects Associated with Exposure 

to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 52 of 69

and death  have been reported following exposure to higher concentrations (50 to 

more than 100 ppm). 

Sensitization

Both skin and respiratory sensitization due to exposure to formaldehyde have been 

reported in the literature. Skin effects may be either acute or chronic, depending on the 

physical form of formaldehyde to which individuals are exposed. Acute effects seem to 

be related to gaseous exposure, resulting in an acute dermatitis which affects the 

eyelids, face, neck, scrotum and flexor surfaces of the arms. The more chronic effects 

have been associated with direct handling of formaldehyde-containing substances (e.g. 

resins), leading to eczema of the hands and arms. The ACGIH documentation states 

that "the skin sensitivity apparently stems from both the direct irritant effect of 

formaldehyde and the development of a true skin/immunological phenomenon". 

Whether formaldehyde is a respiratory sensitizer at low concentrations is less clear, and 

according to the ACGIH, there is not enough information available to establish a 

threshold for respiratory sensitization. In some studies, exposure to formaldehyde via 

inhalation challenge resulted in broncho-constriction and asthma-like symptoms; in 

others, no such responses were observed.

HSE has previously looked at the evidence for the potential for formaldehyde to induce 

occupational asthma (HSE, 1997). The available evidence indicates that although 

formaldehyde has induced asthma in some individuals, the numbers of such cases are 

extremely low in relation to the overall numbers of people exposed. Consequently, 

formaldehyde should not be regarded as a significant cause of occupational asthma.

Repeat Dose Toxicity

In humans, repeated exposure to formaldehyde under occupational or residential 

conditions has led to symptoms associated with irritation of the upper respiratory tract 

and eye at concentrations between 0.1 - 3 ppm. Studies investigating the effect of 

repeated formaldehyde exposure on pulmonary function in humans show little or no 

convincing evidence of any adverse effects, certainly when exposures are less than 

about 1 ppm. In studies reporting changes in pulmonary function, the changes have 

been small (e.g. less than 5 - 10% compared with reference values); exposures in these 

studies range from less than 1 ppm to about 3.5 ppm.

A few studies have undertaken histopathological examination of the nasal epithelium 

(biopsy specimens) in workers exposed to formaldehyde. These studies have 

consistently reported increases in the occurrence of mild nasal epithelial lesions (loss of 

ciliated cells, goblet cell hyperplasia, mild dysplasia) in exposed workers compared with 

unexposed controls. Mean formaldehyde exposures were in the region 0.2 - 2 ppm. 

A large number of repeat dose inhalation studies have been conducted in rats, mice and 

monkeys. In studies in which exposure duration varied between 3 days to 13 weeks, 

damage to and increased cell proliferation in the nasal epithelium is reported. The 

histopathological changes, seen in all species, range from slight hyperplasia and 

squamous cell metaplasia of the ciliated and non-ciliated respiratory epithelium at 
Attachment 1

Appendix C – Chemical Characteristics, Routes of Entry, Biochemical 

Pathways, Chronic and Adverse Health Effects Associated with Exposure 

to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 53 of 69

concentrations of 2 - 3 ppm, to severe rhinitis, necrosis and extensive hyperplasia and 

metaplasia of the nasal epithelium at concentrations of 6 ppm and above. The NOAELs 

for these studies are in the range of 1 - 2 ppm. In the one study involving monkeys, 

exposure to 6 ppm (the only dose level used) for 6 hours/day, 5 days/week for 1 or 6 

weeks, produced histopathological changes and increased epithelial cell proliferation in 

the upper respiratory tract. The effects were more severe after 6 weeks compared with

1 week.

Longer-term inhalation studies (up to 28 months) have also been performed in rodents. 

Non-neoplastic effects observed in these studies range from a minimal degree of 

hyperplasia and squamous cell metaplasia of the nasal respiratory epithelium (reported 

at concentrations between 0.3 - 2 ppm) to rhinitis, necrosis and extensive restorative 

hyperplasia and metaplasia of the nasal respiratory epithelium at concentrations of 6 -

15 ppm. The NOAELs in these studies are generally in the range 1 - 2 ppm.

Mutagenicity

Formaldehyde is genotoxic in vitro at high concentrations. It induces mutations and DNA

damage in bacteria. DNA-protein cross-links, DNA single-strand breaks, chromosomal 

aberrations, sister chromatid exchanges and gene mutations are induced in human and 

rodent cells.

The mutagenic potential of formaldehyde has been well-studied in vivo, with data 

available from both humans and animals. The profile that emerges is consistent with 

formaldehyde acting as a site-of-contact mutagen. Overall, the animal studies show 

negative results in studies of systemic tissues (bone marrow, spleen, leucocytes, 

spermatocytes) but positive results in studies investigating mutagenicity at the site of 

contact (increased incidences of chromosomal aberrations in cells from the lung and GI 

tract). Inhalation of formaldehyde leads to the formation of DNA-protein cross-links in 

the nasal respiratory mucosa of rats and monkeys.

In humans, increased incidences of micronuclei are reported in the cells of the buccal 

cavity and respiratory epithelium, but no increases in chromosome aberrations in 

lymphocytes and no changes in sperm morphology are reported.

Overall, the available data indicate that formaldehyde should be considered as a site-ofcontact mutagen in vivo. This is consistent with its toxicokinetic profile described by 

IARC, 1995, DECOS, 2003 and NEG / DECOS 2003, among others.

Carcinogenicity

Formaldehyde is a reactive alkylating agent and like other alkylating agents which are 

known or suspected carcinogens, it is biologically plausible that formaldehyde may also 

be carcinogenic. Other evidence supporting biological plausibility includes: 

formaldehyde's severe irritancy effects (irritation has been shown to be a potential 

precursor of cancer) and mutagenicity in short-term lab studies.

Formaldehyde is clearly an experimental animal carcinogen, at least in rats, producing 

nasal tumours. In 2-year inhalation studies in rats, no nasal tumours were seen with 
Attachment 1

Appendix C – Chemical Characteristics, Routes of Entry, Biochemical 

Pathways, Chronic and Adverse Health Effects Associated with Exposure 

to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 54 of 69

exposure to 2 ppm but clearly increased incidences of tumours were seen at 10 ppm 

and above. Signs of nasal epithelium inflammation were apparent soon after exposure 

began. The incidence and severity were exposure duration- and concentrationdependent, with such effects seen at concentrations down to 0.3 ppm for 24 months. 

Any carcinogenic potential of formaldehyde is less evident in mice and hamsters. In 

mice, 2/120 males showed nasal tumours following 2-year exposure to 14 ppm 

formaldehyde (103/240 tumours detected in male and female rats under the same 

exposure conditions) whilst no such tumours were seen in 88 male hamsters exposed to 

10 ppm for a lifetime.

No toxicologically significant increases in tumour incidence are reported in reliable oral 

studies in rats or in a dermal study in mice.

Overall, the animal carcinogenicity data on formaldehyde and the available background 

knowledge of other substances that have one or both of the properties of site-of-contact 

genotoxicity and chronic inflammatory potential suggest that the nasal tumours in rats 

most probably arise as a consequence of pronounced chronic irritation of the respiratory 

tract in association with genotoxicity at this site. By extrapolation, a combination of 

these circumstances in humans would be of concern in relation to cancer.

Data in humans are available in the form of a large number of epidemiology studies and 

meta-analyses of groups of studies, some of which are reviewed in this paper. In 2004, 

IARC concluded that there was  ̳sufficient evidence‘ that formaldehyde has caused 

nasopharyngeal cancer in humans (a class 1 carcinogen),  ̳strong but not sufficient 

evidence‘ for a causal association between formaldehyde exposure and leukemia, and 

 ̳limited evidence‘ that formaldehyde has caused sinonasal cancer in humans. The 

available evidence did not support a causal role for formaldehyde having caused cancer 

at any other sites, including the lung. The ACGIH did not come to same conclusion and 

subsequently classified formaldehyde as a class A2 carcinogen – a suspect carcinogen.

A study-by-study appraisal by HSE‘s WATCH (2005) of the studies considered by IARC 

(and as well, studies not referenced by IARC, including papers by Marsh, CIIT), in 

relation to nasopharyngeal cancer was conducted by HSE‘s WATCH (2005), details of 

which are discussed in Appendix B, concludes that although an increased concern for 

the carcinogenic potential of formaldehyde in humans (specifically in relation to 

nasopharyngeal cancer), but that this falls short of providing conclusive evidence that 

formaldehyde exposure has caused nasopharyngeal cancer in humans; there is an 

inconsistent pattern to the findings of the most prominent new studies which lacks a 

clear explanation. Other reviews, including those conducted by DECOS, NEG, NICNAS, 

each have reached a similar conclusion: namely that although some individual studies 

are suggestive of formaldehyde possibly having caused nasopharyngeal or nasal cancer 

in exposed populations, the overall strength of evidence has fallen short of showing a 

clear and causal association. 

A number of reviews that specifically address the apparent association seen in some 

studies between formaldehyde exposure and leukemia were published in 2004. All 

reach the conclusion that formaldehyde is not a causative agent for leukemia (Collins 
Attachment 1

Appendix C – Chemical Characteristics, Routes of Entry, Biochemical 

Pathways, Chronic and Adverse Health Effects Associated with Exposure 

to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 55 of 69

and Lineker, 2004; Heck and Casanova, 2004; Cole and Axten, 2004; Marsh and Youk, 

2004); based on an assessment of the evidence and also on biological plausibility, HSE 

agrees with this position.

Conclusion: Formaldehyde is an experimental animal carcinogen of the upper 

respiratory tract but no other organs or tissues. Although there is an increased concern 

for the carcinogenic potential of formaldehyde in humans the evidence falls short of 

providing conclusive evidence that formaldehyde exposure has caused nasopharyngeal 

cancer in humans.

NOTE: Regulatory authorities responsible for establishing OELs such as the HSE and 

the Deutsche Forschungemeinschaft, consider formaldehyde a genotoxic carcinogen for 

which a threshold can be determined. For more detail refer to Appendix B. 

Reproductive toxicity

Although no fertility studies on formaldehyde have been conducted, repeat dose studies 

have revealed no adverse effects to the reproductive organs. There is no evidence that 

formaldehyde adversely affects fetal development when administered by inhalation, or 

by oral or dermal means. Most recently, no developmental toxicity has been reported in 

two inhalation studies in which rats were exposed to formaldehyde up to 40 ppm 

6 hours/day on days 6 – 20 of gestation or up to 10 ppm 6 hours/day on days 6 - 15 of 

gestation.

Conclusion: Formaldehyde is not considered a reproductive toxin.
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 56 of 69

Workplaces where workers could be exposed to formaldehyde

This appendix covers the types of industries where workers may be exposed to 

formaldehyde, and the levels to which workers have been exposed based on an 

extensive review of WorkSafeBC exposure data as well as that of other jurisdictions, 

including DECOS, Ontario, and other sources. 

In BC, formaldehyde is used in the industries as shown in Table D1. Some industries 

use it in small quantities; for others it is a major component in production. WorkSafeBC 

classification unit identifiers are also shown. 

Table D1: Types of Industries in which workers may be exposed to formaldehyde

Classification Unit 

(CU)

Industry Type

701021 Poultry hatchery

712013 Foundry

713001 Acid, base, salt, chemical, or dye mfg (NES)

713015 Glue or adhesive mfg

713020 Paint, putty, stain, sealant, or varnish mfg

713033 Synthetic resin compound mfg

714001 Cardboard or paper container mfg

714009 Laminated wood structural support product mfg

714012 Oriented strand board mfg

714019 Pressed board manufacture (NES)

714027 Veneer or plywood mfg

714034 Wooden furniture mfg

714042 Woodworking or carpentry shop

714040 Wooden truss mfg

763026 Photo film processing or microfilming

763032 Veterinary hospital, services

764027 Funeral undertaking

765007 University

766001 Acute care
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 57 of 69

Formaldehyde is a widely-used product, finding use in numerous industrial applications. 

Its largest volume use is in the following products:

 Urea-formaldehyde resin/adhesive;

 Phenol-formaldehyde resin/adhesive;

 Plastics manufacturing; and

 Chemical intermediary.

Other uses:

 Preservative for grains and seeds;

 Preservative and drying agent in cosmetics;

 Preservative – biocide in well-drilling fluids;

 Fumigant in egg hatchery room;

 Stabilizer in gasoline;

 Corrosion inhibitor in metal fabrication;

 Photographic film hardener;

 Starch modifier;

 Chemical intermediary for dye manufacturing;

 Embalming preservative;

 Histopathology tissue preservative;

 Antiseptic and fumigant in veterinary medicine; and

 Textile fibre modifier and anti-wrinkle agent.

A review of occupational exposure to formaldehyde in British Columbia, 

Ontario, Quebec and other countries

To determine the extent to which workers were exposed to formaldehyde, the 

WorkSafeBC laboratory database (Laboratory Information Management System – LIMS) 

was reviewed and analyzed for the period of January 1, 1990 to December 31, 2005, 

inclusive. To provide a broader perspective, exposure data from Ontario, Quebec and 

DECOS are also included. 

WorkSafeBC occupational hygiene sampling data for British Columbia workplaces

In total, over 100 WorkSafeBC laboratory analysis summary documents covering in 

excess of 500 individual samples, were analyzed for this evaluation of exposures to 

formaldehyde, covering the period of January 1, 1990 to December 31, 2005. This data 

is based primarily on workplace samples taken during the course of inspection by 

WorkSafeBC occupational hygiene officers. This database covers identifiable exposures 

by workers to the substance in facilities where formaldehyde is used directly (e.g., as a 

solution such as used in histology lab in a hospital) or exposure is to formaldehyde as a 

by-product (e.g., off-gassing of the substance during the curing process of ureaformaldehyde glue in a plywood plant). Data related to exploratory type sampling, such 

as when an occupational hygiene officer is requested to conduct an air quality 

assessment in a facility that does not routinely use formaldehyde, was not included. 

Efforts were made to obtain detail on actual exposure conditions (job type, specific task, 

or area). 

Results are presented as ranges of exposures; that is, the range from lowest to highest 

exposure levels in parts per million is show. Formaldehyde levels below the laboratory 

quantification limit are indicated as ―ND‖ – none detected. Data was grouped on the 
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 58 of 69

basis of the type of industry based on WorkSafeBC‘s CU classification system. The type 

of sampling – area and personal – is also indicated. A personal sample is where a 

worker is wearing a collection device for the duration of the sampling period. An area 

sample is where the collection device is positioned in a fixed location usually in close 

proximity to the worker, usually a stationary work location such as a specific piece of 

equipment (e.g., a MDF press operator station). The point of sampling is to ascertain 

what the worker is exposed to while at the work location – to profile the amount of 

formaldehyde in the worker‘s breathing zone. At times, the intent was to assess 

formaldehyde levels at the point of emission – a location where a worker would not be 

expected to be close proximity to. This is termed ―worst-case sampling‖. There is the 

obvious preference for personal samples since this records the actual real-time 

exposure experienced by the worker during the work shift, or portion thereof. Despite 

some of the inherent limitations of the data, the results do provide insight into the levels 

of formaldehyde to which workers in BC were historically been exposed to. In addition, 

the data are useful as they give a sense of how exposure levels changed over time in 

some of these industries. 

The duration of sampling with the range samples is shown in minutes. 480 minutes 

constitutes full-shift sampling. Due to the fact that the OEL for formaldehyde has been 

primarily based on an 8-hour TWA, very few short term exposure samples have been 

collected. Of the over 500 data points analyzed over the study period only a few 

samples show sample duration of less than 15 minutes. Therefore, this data cannot 

provide a perspective on STEL or Ceiling Limit exposures. 

Due to the limited number of samples taken and other factors, the data does not allow 

statistical analysis. 

Concentrations shown in the following tables are TWA exposures. A TWA reflects all 

the exposures experienced over the duration of the sampling period. The TWA is 

basically an integrated value. As a result, any peaks and valleys the collecting device 

sampled over the duration of the sampling period are ―hidden‖ since a TWA is the 

average concentration for the time period in which the measurement was taken. Thus, 

when comparing these concentrations with the proposed limit, one should keep in mind 

that it is possible that excursions above the limit may have occurred during the sample 

collection period. With TWA readings, it is not possible to determine if Ceiling Limits did 

indeed occur or what the magnitude or duration of those peaks may have been. To do 

this, one must use a direct reading, continuous monitoring device capable of measuring 

and recording data-logged concentrations. 

Table D2 provides a summary of the occupational hygiene sampling surveys conducted 

for formaldehyde for the period of January 1990 to end of December 2005 in a variety of 

industries in British Columbia. Exposures are shown in terms of the TWA since no 

Ceiling Limit determinations were recorded in the LIMS system as a result of the type of 

sampling devices used by the Occupational Health Officers during their exposure 

surveys. The data is shown in two time periods where feasible – a) 1990 to 2000, and b) 

2001 to 2005, allowing one to compare earlier exposure with more recent exposures. 

TWA exposure levels are shown as a range – from the lowest level to the highest level 

recorded. Data allowed Short Term Exposure Limit – STEL determinations for three 

entries. STELs, as defined by regulation, are time-weighted averages for 15 minute 

durations. For the purposes of this report, this includes exposure durations of 4 to 15 

minutes. 
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 59 of 69

Table D2. Formaldehyde Concentrations for the Period January 1990 to December 

2005 in BC Workplaces, based on WorkSafeBC database

Industry Type Time frame Type of 

Sample:

(P)ersonal

(A)rea

Exposure 

Time –

Duration 

(min)

Exposure 

Levels – Range 

(ppm)

Hatchery – poultry (701021) 1995 P 11 – 148 0.1 – 0.35

Sausage mfg (711020) 2003 A 455 – 462 0.055 – 0.18

Foundry (712013) 1995 P 84 – 107 0.20 – 0.24

Foundry (712013) 2001 P 114 – 150 0.010 – 0.012

Foundry (712013) 1995 – 1996 A 80 – 120 0.1 – 0.3

Resin mfg (713015) 1997 P 110 – 308 0.04 – 0.20

Resin mfg (713015) 2005 P 409 – 431 ND – 0.049

Resin mfg (713015) 1997 A 110 – 308 0.05 – 1.10

Paperboard & cardboard mfg 

(714001)

1992 – 1996 A 20 - 153 0.04 – 4.70

Laminated wood products mfg –

included under 714009, 714032, 

714037

1992 – 1998 A 10 – 522 ND – 1.20

Laminated wood products mfg –

included under 714009, 714032, 

714037

2001 A 117 – 133 ND

Laminated wood products mfg –

included under 714009, 714032, 

714037

1996 – 1998 P 90 - 499 0.01 – 1.20

Laminated wood products mfg –

included under 714009, 714032, 

714037

2005 P 437 – 455 0.239 – 0.381

Oriented strand board (714012) 2002 A 19 -132 0.099 – 1.420

Oriented strand board (714012) 1996 – 1997 P 102 – 182 0.10 – 0.30

Oriented strand board (714012) 1997 – 1999 P 15 – 455 0.03 – 0.32

Pressed fibre board, MDF (714019) 1996 – 2000 A 15 – 455 0.07 – 5.00

Plywood (714027) 1992 – 1997 A 15 – 500 ND – 0.99

Plywood (714027) 2002 – 2003 A 30 – 490 ND – 0.069

Plywood (714027) 1997 – 1999 P 88 – 129 ND – 0.249
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 60 of 69

Industry Type Time frame Type of 

Sample:

(P)ersonal

(A)rea

Exposure 

Time –

Duration 

(min)

Exposure 

Levels – Range 

(ppm)

Plywood (714027) 2002 P 112 – 129 0.086 – 0.220

Funeral undertaking (764027) 1990 – 1991 A 105 – 150 0.30 – 1.60

Funeral undertaking (764027) 1991 P 135 – 166 0.110 – 0.166

Funeral undertaking (764027) 2003 – 2004 A 84 – 86 0.485 – 0.600

Funeral undertaking (764027) 2003 – 2004 P 84 – 350 ND – 0.737

University (765007) 1998 P 26 – 84 0.520 – 0.702

University (765007) 1998 P 10 – 15 (STEL) 0.52 – 1.15

Hospital & medical clinic (766001, 

766015)

1990 – 2000 A 14 – 445 ND – 0.96

Hospital & medical clinic (766001, 

766015)

2001 – 2003 A 92 – 445 ND – 0.96

Hospital & medical clinic (766001, 

766015)

1994 – 1998 A 5 (STEL) 3.0 – 5.2

Hospital & medical clinic (766001, 

766015)

1990 – 2000 P 23 – 450 ND – 0.48

Hospital & medical clinic (766001, 

766015)

2001 – 2003 P 90 – 435 0.03 – 0.35

Hospital & medical clinic (766001, 

766015)

2000 – 2001 P 4 – 15 (STEL) 0.02 – 1.35

ND = none detected – below the detection limit of the analytical instrument or laboratory method

The results indicate that industries in which exposure levels were predominantly below 

the current 0.3 ppm 8-hour TWA OEL include:

 Foundries

 Resin manufacturing

 Plywood manufacturing.

Industries in which the current 0.3 ppm 8-hour TWA OEL was exceeded at times 

include:

 Poultry hatcheries

 Paperboard & cardboard manufacturing

 Laminated wood products manufacturing

 Pressed (particle / fibre) board manufacturing

 Oriented strand board manufacturing

 Funeral homes

 Universities

 Hospitals & medical clinics. 
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 61 of 69

The data also allows comparison of changes over time for some of the industries. 

Foundries, resin-, laminated wood-, plywood-manufacturing, and hospitals demonstrate 

an improvement over the earlier time period. In terms of the three STELs shown, 

workers would be over-exposed if the STEL OEL was established at 1.0 ppm or 

2.0 ppm, particularly for hospitals. Levels up to 5.0 ppm can be expected during cleanup of spills of formaldehyde solution (histology) in a laboratory or surgical suite. 

Other BC-based occupational hygiene survey 

BC resin manufacturing plant survey with an electronic direct reading monitor, 

November 1996 – May 1997

Levels of formaldehyde at a formaldehyde-based resin manufacturing, taken by 

WorkSafeBC, were measured with a ―formaldemeter‖ – a direct reading rapid response 

electronic instrument capable of providing near instantaneous measurements of 

formaldehyde. It can thus be used to determine if the Ceiling Limit is exceeded. 

Table D3 shows formaldehyde readings – spot readings – for the period covering 

November 1996 to May 1997. 

Table D3: Spot readings - Formaldehyde levels at a BC resin manufacturing plant 

during 1996 and 1997

Date No. of Samples Range of Results (ppm) for 

Formaldehyde

Nov 96 7 0.13 – 0.35

Dec 96 7 0.10 – 0.38

Feb 97 7 0.02 – 0.36

Mar 97 7 0.02 – 0.36

April 97 7 0.04 – 0.38

May 97 7 0.03 – 0.40

As shown in the table, a Ceiling Limit of 0.3 ppm would be exceeded at least once on 

every sampling occasion over the time period shown. Of the 42 instantaneous area 

measurements taken by the formaldemeter, 6 exceeded 0.3 ppm. These excursions 

consistently occurred in the same area of the plant — specifically, in or around the dry 

products building. Of the 30 personal samples taken, only one yielded a concentration 

greater than 0.3 ppm; this measurement was taken on the shipper/receiver. It is evident 

that for most areas of the plant and for most jobs compliance with a time-weighted 

average or ceiling exposure limit of 0.3 ppm is achievable for this plant. 
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 62 of 69

Occupational exposure data on formaldehyde – Ontario 

Table D4. Formaldehyde exposure levels in plywood and pressed board products 

manufacturing, September 2002 (Ontario Ministry of Labour)

Location Date 8-hour TWA 

reading (ppm)

Range

MVUE1(LCL2, 

UCL3)

15-minute STEL 

reading (ppm)

Range

MVUE1(LCL2, 

UCL3)

Formaldehyde 

Instantaneous 

Ceiling Limit 

reading (ppm)

Range

MVUE1(LCL2, UCL3)

Company A

Particle board 

plant

Sept. 9, 

2002

0.07 – 0.20

0.146 (0.110, 0.228)

0.15 – 0.54

-----

0.18 – 7.47

1.435 (0.941, 3.110)

Company B

Plywood plant

Sept. 11, 

2002

0.16 – 0.17

0.164 (0.159, 0.169)

0.14 – 0.29

0.205 (0.153, 0.348)

0.33 – 0.44

0.357 (0.332, 0.387)

Company C

Particle board 

plant 

Sept. 11, 

2002

0.08 – 0.11

0.090 (0.077, 0.110)

0.14 – 0.29

-----

0.17 – 0.50

0.309 (0.268, 0.369)

Company D

Oriented strand 

board (OSB) plant

Sept. 12, 

2002

0.03 – 0.08

0.054 (0.042, 0.082)

0.24 – 0.26

-----

0.09 – 0.97

0.391 (0.315, 0.542)

Calculations completed by PRD. 

1 MVUE = estimated arithmetic means, lognormal parametric. Blanks indicate too few data points to allow 

statistical calculations.

2

LCL = 95% lower confidence limit (LCL1,95%)

3 UCL = 95% upper confidence limit (UCL1,95%)

The Ontario exposure data indicated that the current 8-hour TWA of 0.3 ppm for 

formaldehyde was not exceeded in either of the two particle board plants, plywood mill, 

or oriented strand board plant. On the other hand, instantaneous readings show that the 

ACGIH-TLV Ceiling Limit of 0.3 ppm would be exceeded on most occasions; certainly 

the arithmetic means are exceeded for all plants, with particle board plant ―A‖ showing 

the highest arithmetic mean, based on 19 samples. Spot readings were recorded as 

high as 7.47 ppm at this plant. This reading was taken at the press outfeed and flying 

cut-off saw location. The exhaust fan servicing the press outfeed (used to control 

formaldehyde levels at the point of emission) was not functioning at the time of the 

survey. This is an important observation to consider – if exhaust air extraction systems 

are not operating, the potential for worker over-exposure is greatly increased. 

Based on the arithmetic means for instantaneous readings, the current Ceiling of 

1.0 ppm was not exceeded in all plants with the exception of Plant A – the particle board 

plant. As noted in the source document, during the survey conducted at the oriented 

strand board plant, several roof fans were noted running in reverse and the press area 

was not receiving enough make-up air (an adequate supply needs to be delivered to 

compensate for the quantities of air pulled through the exhaust system(s) servicing the 

press). 
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 63 of 69

Quebec exposure data on formaldehyde collected at pressed (particle / oriented 

strand / medium density fibre) board manufacturing plants - 2001 & 2002 

As part of an extensive health study on the impact of changing occupational exposure 

limits for formaldehyde, the IRSST funded several occupational hygiene surveys of 

workplace in that province. Past and present formaldehyde measurements made in 

various pressed wood manufacturing plants in Quebec were studied as part of an 

evaluation of the health effects undertaken in Quebec in order to determine worker 

exposure levels. This study, as summarized in Table D5, is part of a larger report 

(Lavoue, et al, 2003).

Table D5. Formaldehyde exposure levels at Quebec oriented-strand board (OSB), 

medium density fibre board (MDF) and particle board (PB) plants – 2001 to 2002. 

Type of 

Plant 

Job Title, Location (P)ersonal or 

(A)rea Sample

Exposure Level1

Geometric Mean

Oriented 

Strand 

Board 

Plant

Asst. press operator P 0.04 / 0.07

Shipper P 0.06 / 0.10

Finisher P 0.05 / 0.07

Press operator P 0.03 / 0.08

Maintenance worker P 0.06 / 0.08

Chip preparer P 0.04 / 0.11

Storage / shipping A 0.04 / 0.06

Finishing A 0.09 / 0.09

Main Production area A 0.05 / 0.15

Resin production storage A 0.05 / 0.09

Raw material – chip preparation A 0.08 / 0.10

Medium 

Density 

Fibre 

Board 

Plant 

Asst. press operator P 0.09 / 0.27

Shipper P ------ 0.19

Finisher P 0.16 / 0.24

Maintenance worker P 0.12 / 0.11

Resin operator P 0.22 / 0.34

Storage / shipping A 0.17 / 0.37
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 64 of 69

Type of 

Plant 

Job Title, Location (P)ersonal or 

(A)rea Sample

Exposure Level1

Geometric Mean

Finishing A 0.22 / 0.33

Main Production area A 0.26 / 0.75

Resin production storage A ------ 0.35

Raw material – chip preparation A 0.16 ------

Particle 

Board 

Plant

Asst. press operator P 0.20 / 0.28

Shipper P 0.16 / 0.20

Finisher P 0.19 / 0.26

Maintenance worker P 0.10 / 0.22

Resin operator P 0.16 / 0.41

Flat mill operator P 0.12 / 0.17

Storage / shipping A 0.09 / 0.17

Finishing A 0.20 / 0.29

Main production A 0.75 / 0.56

Resin production storage A 0.08 / 2.00

Raw material – chip preparation A 0.42 / 0.03

1

The values shown are based on samples collected by both the Quebec government occupational hygiene 

inspectors (CSST) (column 1) and research scientists IRSST) data (Lavoue, et al, 2003.

The Quebec research team collected 275 samples during 2001 – 2002 while 590 

measurements dating back to 1984 were obtained from government records 

(Commission of Health & Occupational Safety – CSST). The area measurements had a 

global geometric mean of 0.28 ppm while that for personal samples was 0.17 ppm. 

Higher levels were found in the government data as compared to research data. This 

sampling bias is most likely due to the fact that government occupational hygienists tend 

to sample ―worst-case‖ exposures. This observation can also be applied to the 

WorkSafeBC data – there is a ―worst-case‖ sampling bias. Proximity to the press and 

processes resulted in the highest exposures. Overall, exposure levels are below BC‘s 

current 0.3 ppm TWA OEL for the Quebec oriented strand board industrial plants 

studied. There are some exposures in excess of BC‘s 8-hour TWA OEL recorded for the 

medium density fibre board and particle board plants, but most are below the BC-based 

8-hour TWA OEL of 0.3 ppm. However, these exposure levels are based on timeweighted averaged measurements. The data does not provide any information on 

instantaneous peaks that may have occurred during the time the sample was being 

taken. 
Attachment 1

Appendix D – Workplace Exposure to Formaldehyde

July 2009 – OEL for formaldehyde Policy and Research Division Page 65 of 69

DECOS 2003 Formaldehyde Exposure Data

DECOS completed an extensive health study on formaldehyde in 2003. The report 

includes an extensive summary of exposure data – much of it dates back over 20 years 

ago. Some of this data is shown Table D6 for a number of different industries of interest 

to the situation in BC. 

Table D6. Formaldehyde exposure data in various industries (DECOS, 2003)

Industry Date Job / task or work area (P)ersonal 

or (A)rea 

sample

Exposures to 

Formadehyde

Range – ppm

Formaldehyde resin 

mfg

1980

1980

1983

Plant work areas - various A

P

A

0.05 – 0.37

0.06 – 5.40

0.12 – 0.89

Plywood & particle 

board

1979 Plant work areas - various A 1.0 – 2.5

Wood furniture mfg 1983 particle board veneering A 0.008 – 6.40

Paper & paperboard 

mfg

1976 Paper treatment – resin 

impregnation

P

A

0.01 – 0.23

0.04 – 0.08

Foundry 1976 Core machine operators

Moulding

P

P

0.07 – 18.30

0.03 – 0.78 

Fiberglass insulation 1980 Installers P 0.007 – 0.33

Funeral home 1975

1980

Embalmers A

P

0.09 – 5.26

0.20 – 3.99

Hospital 1975

1975

1979

Autopsy P

A

A

0.57 – 1.58

0.13 – 13.57

2.20 – 7.90

University 1983 Animal dissection P

A

<0.38 – 1.04

0.05 – 0.40

DECOS provided no recent exposure data. Very high levels were recorded, particularly 

during autopsy work in hospitals and for core machine operators in foundries. For the 

latter, exposure is via the urea or phenol formaldehyde thermosetting resin binder used 

in forming the sand-based moulds for that industry. Currently, low-emission ureaformaldehyde / phenol-formaldehyde thermosetting resin binders are being used in the 

foundry industry and exposure levels are correspondingly lower. This data indicates 

how much lower the exposure levels have become over the years. 
Attachment 1

Appendix E – List of References (partial)

July 2009 – OEL for formaldehyde Policy and Research Division Page 66 of 69

ACGIH (American Conference of Governmental Hygienists): 2006 TLVs and BEIs Based 

on the Documentation of the Threshold Limit Values for Chemical Substances and 

Physical Agents & Biological Exposure Indices. 2006: ISBN: 1-882417-62-3. ACGIH, 

Cincinnati, OH, USA.

ACGIH (2001). Documentation of the Threshold Limit Values and Biological Exposure

Indices. 7th Edition. American Conference of Industrial Hygienists. Cincinnati. 26 p.

ASTDR (Agency for Toxic Substance & Disease Registry) / EPA (Environmental 

Protection Agency) (1999). Toxicological profile for formaldehyde. Dept of Health and 

Human Services. Publication July 1999. 468 p.

Arts, JHE, MAJ Rennen, C de Heer (2006). Inhaled formaldehyde: evaluation of sensory 

irritation in relation to carcinogenicity. Reg Toxicol Pharm 44:144-60. (A research group 

of the TNO – the Netherlands Organization for Applied Scientific Research).

BfR (Bundesinstitut für Risikobewertung) (2006). Assessment of the Carcinogenicity of 

Formaldehyde. Federal Institute for Risk Assessment. Berlin. 156 p.

Blair, A, PA Stewart, RN Hoover, JF Fraumeni, J Walrath, M O‘Berg, W Gaffey (1987). 

Cancers of the nasopharynx and oropharynx and formaldehyde exposure. J Nat Cancer 

Inst 76:1071-84.

CIIT (Chemical Industry Institute of Toxicology) (1999). Formaldehyde: Hazard 

Classification and Dose-Response Assessment for Carcinogenicity by the Route of 

Inhalation. Research Triangle Park, USA. 336 p.

Coggon, D, EC Harris, J Poole, KT Palmer (2003). Extended follow-up of a cohort of 

British chemical workers exposed to formaldehyde. J Nat Cancer Inst 95:1608-15. 

Cole, P, C Axten (2004). Formaldehyde and leukemia: an improbable causal 

relationship. Regul Toxicol Pharm 40:107-12.

Collins, JJ, GA Lineker (2004). A review of the meta-analysis exposure and leukemia. 

Regul Toxicol Pharm 40:81-91.

Conolly, RB, JS Kimbell, DB Jantzen, FJ Miller (2002). Dose response for 

formaldehyde-induced cytotoxicity in the human respiratory tract. Regul Toxicol Pharm 

35:32-43.

Conolly, RB, JS Kimbell, D Janszen, PM Schlosser, D Kalisak, J Preston, FJ Miller 

(2004). Human respiratory tract cancer risks of inhaled formaldehyde: dose response 

predictions from biologically-motivated computational modeling of a combined rodent 

and human dataset. Toxicol Sci 82:279-96. 
Attachment 1

Appendix E – List of References (partial)

July 2009 – OEL for formaldehyde Policy and Research Division Page 67 of 69

DECOS (Dutch Expert Committee on Occupational Standards) (2003). Formaldehyde –

Health-based recommended occupation exposure limit. Health Council of the 

Netherlands, The Hague. Publ No 2003/02OSH. 129 p.

ECOTEC (European Centre for Ecotoxicology and Toxicology of Chemicals) (1995). 

Technical Report No 65: Formaldehyde and Human Cancer Risk. ISSN-0773-8072-65.

Environment Canada, Health Canada (2001). Priority Substance List Assessment 

Report on Formaldehyde. CEPA Registry, Ministry Public Works & Government 

Services, Ottawa, Canada. 102 p.

EPHC (Environmental Protection & Heritage Council) (2003). Formaldehyde Health 

Review. National Environment Protection Measures – Air Toxics. Australia. 26 p.

Hauptmann, M., LB Freemen, JH Lubin, PA Stewart & A Blair (2005). Briefing 

Document: Update of the NCI cohort of workers in formaldehyde industries. National 

Cancer Institute. Available from the NCI website.

Hauptmann, M., JH Lubin, PA Stewart, RB Hayes & A Blair (2003). Mortality from solid 

cancers among workers in formaldehyde industries. Am J Epid 159:1117-30.

Heck, HA, M Casanova (2004). The implausibility of leukemia induction by 

formaldehyde: a critical review of the biological evidence on distant-site toxicity. Regul 

Toxicol Pharm 40:92-106.

IARC (International Agency for Research on Cancer) (1995). Formaldehyde. IARC 

Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 62. Lyon, France, 

pp. 217-362.

IARC (2005). Monographs on the Evaluation of Carcinogenic Risk to Humans: 

Formaldehyde, 2-Butoxyethanol, 1-tert-Butoxy-2-propanol. Vol 88, Lyons, France.

IRSST (Institute de Reserche Robert Sauvé en Santé et en Sécurité du Travail) (2004; 

2006 English edition). Impact of Lowering the Permissible Exposure Value for 

Formaldehyde – Health Impact of an Occupational Exposure to Formaldehyde. 

Université de Montréal. IRSST Report # RA13-386. Montreal, Quebec. 113 p. 

Lavoue J, C Beaudry, N Goyer, G Perrault, M Gerin (2003). Investigation of 

determinants of past and current exposures to formaldehyde in the reconstituted wood 

panel industry in Quebec. Ann Occup Hyg. 49:1-16. 

Liteplo, RG, ME Meek (2003). Inhaled formaldehyde: exposure estimation, hazard 

characterization, and exposure-response analysis. J Tox Env Hlth, Part B Crit Rev. 

6:85-114.

MAK Commission (2002). Formaldehyde, in Occupational Toxicants – Critical Data 

Evaluation for MAK Values and Classification of Carcinogens. Edited by H Greim. 
Attachment 1

Appendix E – List of References (partial)

July 2009 – OEL for formaldehyde Policy and Research Division Page 68 of 69

Volume 17:164-201. Deutsche Forschungsgemeinschaft. Wiley-VHC Verlag GmbH &

Co. KGaA, Weinheim.

MAK Commission (2006). Formaldehyde, IN Essential MAK Value Documentation from 

the MAK Collection for Occupational Health and Safety. Edited by H Greim. Deutsche 

Forschungsgemeinschaft (DFG). Wiley-VHC Verlag GmbH & Co. KGaA, Weinheim. pp 

269-309. 

Marsh, GM, RA Stone, NA Esmen, VL Henderson, K Lee. 1996. Mortality among 

chemical workers in a factory where formaldehyde was used. Occup Environ Med 

53:613-627.

Marsh, GM. 1992. Lung cancer mortality among industrial workers exposed to

formaldehyde: a poisson regression analysis of the National Cancer Institute study. Am 

Indust Hyg Assoc 53:681-91.

Marsh, GM, AO Youk, JM Buchanich, LD Cassidy, LJ Lucas, NA Esmen and IM Gathura 

(2002). Pharyngeal cancer mortality among chemical plant workers exposed to 

formaldehyde. Tox Indust Hlth 18:257-68. 

Marsh, GM, AO Youk (2004). Reevaluation of mortality risks in the leukemia cohort 

study of the National Cancer Institute. Regul Toxicol Pharm 40:113-124.

Marsh, GM, AO Youk (2005). Reevaluation of mortality risks from nasopharyngeal 

cancer in the formaldehyde cohort study of the National Cancer Institute. Regul Toxicol 

Pharm 42:275-383.

NEG / DECOS (Northern Expert Group) / (Dutch Expert Committee on Occupational 

Standards). 2003. Criteria Document 132: Formaldehyde. Nordic Council of Ministers. 

Arbete Och Hälsa, Vetenskaplig Skriftserie. ISNB 91-7045-689-9. 76 p. 

NICNAS (National Industrial Chemicals Notification and Assessment Scheme) (2005). 

NICNAS Response to Requests for Variation of the Draft Formaldehyde Report. Dept. 

Health & Ageing, Australia Government. 

OSHA (1992). Occupational Exposure to Formaldehyde. 29 CFR 1910 Final Rule.

Available from the OSHA website.

Paustenbach D, Y Alarie, T Kulle, N Schachter, R Smith, J Swenberg, H Witschi, and SB 

Harowitz (1997). A recommended occupational exposure limit for formaldehyde based 

on irritation. J Toxicol Environ Health. 50:217-263.

Pinkerton, LE, MJ Hein, T Stayner (2004). Mortality among a cohort of garment workers 

exposed to formaldehyde: an update. Occup Environ Med 61:193-200. 

SCOEL (Scientific Committee on Occupational Exposure Limits) (2006). 

Recommendation from the Scientific Committee on Occupational Exposure Limits for 
Attachment 1

Appendix E – List of References (partial)

July 2009 – OEL for formaldehyde Policy and Research Division Page 69 of 69

Formaldehyde. Employment, Social Affairs & Equal Opportunties, European 

Commission, EU. 19 p. 

WATCH (Working Group on Action to Control Chemicals) Committee. 2005. The 

carcinogenicity of formaldehyde. A subcommittee report to the Advisory Committee on 

Toxic Substances, Health & Safety Commission, United Kingdom.

WATCH (Working Group on Action to Control Chemicals) Committee. 2006. Genotoxic 

carcinogens and REACH – DNELS and DMELS. A subcommittee report to the Advisory 

Committee on Toxic Substances, Health & Safety Commission, United Kingdom.

WHO (World Health Organization) (2003). Formaldehyde. A CICAD (Concise 

International Chemical Assessment Document) No. 40. International Programme on 

Chemical Safety (IPSC).