forty - four building construction workers were recruited with the help of company safety officers or similar from two large building construction companies ( at least 5 were young apprentices ) .
seventeen electricians were recruited from one large building construction company and one small contractor through safety officers and through a representative from the swedish electrical contractors association .
eight bricklayers from one large building enterprise and one small contractor were recruited ; one group was mostly spanish - speaking .
also , 15 loose wool insulation workers from two small contractors and 8 pipe and ventilation workers from one single ventilation contractor were recruited .
fourteen private consumers were recruited : 11 were customers at retail stores who were invited after they had bought insulation materials , and 3 were colleagues or friends of the authors with recent experience of performing mmvf insulation tasks .
overview of the study with focus groups and structured interviews concerning skin discomfort caused by man - made vitreous fibres ( mmvfs ) by profession , work task , and use of different mmvf materials all had experience of working with rock or stone wool ( green or grey ) and with yellow glass wool .
experience with white glass wool and groups with female workers , foremen or other types of personnel are shown in the notes column . *
company i d : a , peab ab ; b , skanska ; c , jm ab ; d , sprutab ab ; e , ab isolerservice ; f , stersj elektriska ab ; g , universialisolering fredriksson ab .
an overview of types of interview , number of participants and tasks is given in table1 .
1 . some occupational insulation tasks : inner roof insulation ( a ) , cutting a batt for inner room insulation ( b ) , cutting a ventilation insulation batt ( c ) , and installing ventilation pipe insulation ( d ) . interviews
( n  =  11 ) were performed to test questions and gather information on working tasks and available fibrous insulation products . in total , 12 focus group sessions were performed during 20092010 : 
 six groups ( one with apprentices only ) with building construction workers at two large construction companies ( n  =  33).two groups of facade insulators ( bricklayers ) ( n  =  8)   
employees at a large building construction company and a small contractor.two groups of loose wool insulators ( n  =  15 ) from two contractors.two groups of electricians ( n  =  17 )    employees at a large building construction company and one small contractor . 
 
six groups ( one with apprentices only ) with building construction workers at two large construction companies ( n  =  33 ) .
two groups of facade insulators ( bricklayers ) ( n  =  8)    employees at a large building construction company and a small contractor . two groups of loose wool insulators (
two groups of electricians ( n  =  17 )    employees at a large building construction company and one small contractor .
each focus group interview lasted between 35 and 70  min , and they were conducted at the construction site or in a facility provided by the companies .
) first read and reflected separately on the text , and a discussion then followed , where quotes indicating some major opinions were identified and categorized .
structured interviews were performed during 20082010 : 
 do - it - yourself consumers ( n  =  14 ) were interviewed by telephone .
only persons who had purchased mmvf products and insulated within the last year were interviewed .
the original intention was to perform this as a focus group interview , but , logistically , this was not possible.pipe and ventilation insulators ( n  =  8) at a medium - sized ventilation contractor were interviewed .
do - it - yourself consumers ( n  =  14 ) were interviewed by telephone .
only persons who had purchased mmvf products and insulated within the last year were interviewed .
the original intention was to perform this as a focus group interview , but , logistically , this was not possible .
pipe and ventilation insulators ( n  =  8) at a medium - sized ventilation contractor were interviewed .
four teachers at two swedish high schools construction programmes were interviewed about their tuition concerning insulation and the use of mmvfs .
the interviews were audio-recorded.occupational hygiene specialists at different construction companies , union representatives , safety officers and personnel working with occupational health care , in total 12 persons , were interviewed .
their opinions were not used as a separate input , but they contributed valuable information . 
 
four teachers at two swedish high schools construction programmes were interviewed about their tuition concerning insulation and the use of mmvfs .
occupational hygiene specialists at different construction companies , union representatives , safety officers and personnel working with occupational health care , in total 12 persons , were interviewed .
their opinions were not used as a separate input , but they contributed valuable information .
the main questions were developed on the basis of a literature survey , expert consultations , and experience from the pilot structured interview .
the following main questions and topics ( see questions a , b , and c ) were discussed during the focus group interviews , and were highlighted in the structured interviews .
as the number of participants in the structured interviews was small , and only covered pipe and ventilation insulators ( n  =  8) and do - it - yourself consumers ( n  =  14 ) , as compared with the number of focus group participants ( n  =  73 ) , who covered different professions , no extensive evaluation of the outcome from the structured interviews was performed .
question a : which mmvf material or product in use causes the most skin discomfort ?
question b : what task / working position / situation causes the most skin discomfort ?
question c : where on the body do you experience discomfort most ? during the focus group interviews , we tried to avoid opinions and discussions concerning working with glass fibre - reinforced wet room boards and wet - area plasterboards .
effects caused by inhalation of fibres were also outside the scope of the interviews 25,2022 .
the study was approved by the regional ethical review board in stockholm , sweden ( epn 2009/680 - 31/2 ) , and all participants gave their informed consent .
a total of 106 participants were recruited by purposive sampling in order to obtain information from subjects with actual experience of handling currently used mmvf materials ( table1 ) .
they were construction workers in different professions or do - it - yourself consumers aged between 18 and 65  years .
forty - four building construction workers were recruited with the help of company safety officers or similar from two large building construction companies ( at least 5 were young apprentices ) .
seventeen electricians were recruited from one large building construction company and one small contractor through safety officers and through a representative from the swedish electrical contractors association .
eight bricklayers from one large building enterprise and one small contractor were recruited ; one group was mostly spanish - speaking .
also , 15 loose wool insulation workers from two small contractors and 8 pipe and ventilation workers from one single ventilation contractor were recruited .
fourteen private consumers were recruited : 11 were customers at retail stores who were invited after they had bought insulation materials , and 3 were colleagues or friends of the authors with recent experience of performing mmvf insulation tasks .
overview of the study with focus groups and structured interviews concerning skin discomfort caused by man - made vitreous fibres ( mmvfs ) by profession , work task , and use of different mmvf materials all had experience of working with rock or stone wool ( green or grey ) and with yellow glass wool .
experience with white glass wool and groups with female workers , foremen or other types of personnel are shown in the notes column . *
company i d : a , peab ab ; b , skanska ; c , jm ab ; d , sprutab ab ; e , ab isolerservice ; f , stersj elektriska ab ; g , universialisolering fredriksson ab .
an overview of types of interview , number of participants and tasks is given in table1 .
1 . some occupational insulation tasks : inner roof insulation ( a ) , cutting a batt for inner room insulation ( b ) , cutting a ventilation insulation batt ( c ) , and installing ventilation pipe insulation ( d ) . interviews
( n  =  11 ) were performed to test questions and gather information on working tasks and available fibrous insulation products . in total , 12 focus group sessions were performed during 20092010 : 
 six groups ( one with apprentices only ) with building construction workers at two large construction companies ( n  =  33).two groups of facade insulators ( bricklayers ) ( n  =  8)    employees at a large building construction company and a small contractor.two groups of loose wool insulators ( n  =  15 ) from two contractors.two groups of electricians ( n  =  17 )    employees at a large building construction company and one small contractor . 
  six groups ( one with apprentices only ) with building construction workers at two large construction companies ( n  =  33 ) .
two groups of facade insulators ( bricklayers ) ( n  =  8)    employees at a large building construction company and a small contractor .
two groups of loose wool insulators ( n  =  15 ) from two contractors . two groups of electricians ( n  =  17 )    employees at a large building construction company and one small contractor .
each focus group interview lasted between 35 and 70  min , and they were conducted at the construction site or in a facility provided by the companies .
) first read and reflected separately on the text , and a discussion then followed , where quotes indicating some major opinions were identified and categorized .
structured interviews were performed during 20082010 : 
 do - it - yourself consumers ( n  =  14 ) were interviewed by telephone .
only persons who had purchased mmvf products and insulated within the last year were interviewed .
the original intention was to perform this as a focus group interview , but , logistically , this was not possible.pipe and ventilation insulators ( n  =  8) at a medium - sized ventilation contractor were interviewed .
do - it - yourself consumers ( n  =  14 ) were interviewed by telephone .
only persons who had purchased mmvf products and insulated within the last year were interviewed .
the original intention was to perform this as a focus group interview , but , logistically , this was not possible .
pipe and ventilation insulators ( n  =  8) at a medium - sized ventilation contractor were interviewed .
four teachers at two swedish high schools construction programmes were interviewed about their tuition concerning insulation and the use of mmvfs .
the interviews were audio-recorded.occupational hygiene specialists at different construction companies , union representatives , safety officers and personnel working with occupational health care , in total 12 persons , were interviewed .
their opinions were not used as a separate input , but they contributed valuable information . 
 
four teachers at two swedish high schools construction programmes were interviewed about their tuition concerning insulation and the use of mmvfs .
occupational hygiene specialists at different construction companies , union representatives , safety officers and personnel working with occupational health care , in total 12 persons , were interviewed .
their opinions were not used as a separate input , but they contributed valuable information .
interviews ( n  =  11 ) were performed to test questions and gather information on working tasks and available fibrous insulation products .
in total , 12 focus group sessions were performed during 20092010 : 
 six groups ( one with apprentices only ) with building construction workers at two large construction companies ( n  =  33).two groups of facade insulators ( bricklayers ) ( n  =  8)    employees at a large building construction company and a small contractor.two groups of loose wool insulators ( n  =  15 ) from two contractors.two groups of electricians ( n  =  17 )    employees at a large building construction company and one small contractor . 
  six groups ( one with apprentices only ) with building construction workers at two large construction companies ( n  =  33 ) . two groups of facade insulators ( bricklayers ) ( n  =  8)    employees at a large building construction company and a small contractor . two groups of loose wool insulators ( n  =  15 ) from two contractors . two groups of electricians ( n  =  17 )    employees at a large building construction company and one small contractor .
each focus group interview lasted between 35 and 70  min , and they were conducted at the construction site or in a facility provided by the companies .
) first read and reflected separately on the text , and a discussion then followed , where quotes indicating some major opinions were identified and categorized .
structured interviews were performed during 20082010 : 
 do - it - yourself consumers ( n  =  14 ) were interviewed by telephone .
only persons who had purchased mmvf products and insulated within the last year were interviewed .
the original intention was to perform this as a focus group interview , but , logistically , this was not possible.pipe and ventilation insulators ( n  =  8) at a medium - sized ventilation contractor were interviewed .
do - it - yourself consumers ( n  =  14 ) were interviewed by telephone .
only persons who had purchased mmvf products and insulated within the last year were interviewed .
the original intention was to perform this as a focus group interview , but , logistically , this was not possible .
pipe and ventilation insulators ( n  =  8) at a medium - sized ventilation contractor were interviewed .

 four teachers at two swedish high schools construction programmes were interviewed about their tuition concerning insulation and the use of mmvfs .
the interviews were audio-recorded.occupational hygiene specialists at different construction companies , union representatives , safety officers and personnel working with occupational health care , in total 12 persons , were interviewed .
their opinions were not used as a separate input , but they contributed valuable information . 
 
four teachers at two swedish high schools construction programmes were interviewed about their tuition concerning insulation and the use of mmvfs .
occupational hygiene specialists at different construction companies , union representatives , safety officers and personnel working with occupational health care , in total 12 persons , were interviewed .
their opinions were not used as a separate input , but they contributed valuable information .
the main questions were developed on the basis of a literature survey , expert consultations , and experience from the pilot structured interview .
the following main questions and topics ( see questions a , b , and c ) were discussed during the focus group interviews , and were highlighted in the structured interviews . as the number of participants in the structured interviews was small , and only covered pipe and ventilation insulators (
n  =  8) and do - it - yourself consumers ( n  =  14 ) , as compared with the number of focus group participants ( n  =  73 ) , who covered different professions , no extensive evaluation of the outcome from the structured interviews was performed .
question a : which mmvf material or product in use causes the most skin discomfort ?
question b : what task / working position / situation causes the most skin discomfort ?
question c : where on the body do you experience discomfort most ? during the focus group interviews , we tried to avoid opinions and discussions concerning working with glass fibre - reinforced wet room boards and wet - area plasterboards .
effects caused by inhalation of fibres were also outside the scope of the interviews 25,2022 .
the study was approved by the regional ethical review board in stockholm , sweden ( epn 2009/680 - 31/2 ) , and all participants gave their informed consent .
the most typical comments and opinions concerning the three main questions in the focus groups are shown in tables24 , separately for different professions or tasks .
the comments are listed as direct citations ( originally in colloquial swedish ) as recorded during the focus group sessions .
focus group interviews concerning work with man - made vitreous fibres ( mmvfs ) and skin discomfort ; some of the most typical comments and opinions concerning question a ,  which mmvf material or product in use causes the most skin discomfort? focus group interviews concerning work with man - made vitreous fibres and skin discomfort ; some of the most typical comments and opinions concerning question b , 
what task / working position / situation causes the most discomfort? focus group and structured interviews concerning work with man - made vitreous fibres and skin discomfort ; some of the most typical comments and opinions concerning question c ,  where on the body do you experience discomfort most? the structured interviews with do - it - yourself consumers showed that most informants ( 11/14 ) reported some discomfort .
one person stated that the yellow fibrous material was most troublesome ( question a ) ; 1 felt that inner roof insulation was troublesome ( question b ) .
the majority of the informants ( 11 of 14 ) said that the skin discomfort was felt most on the hands , forearms , and neck ( question c ) , and occasionally in the eyes .
one person who reported having had atopic eczema did not report any skin problems related to mmvfs .
two of the pipe and ventilation insulators ( 2/8 ) reported some skin discomfort , and all of them worked mostly with green / grey fibrous products .
some other often discussed topics are shown in tables5 and 6 . some selected and typical comments on topics often discussed during focus group or structured interviews on work with man - made vitreous fibres and skin discomfort some more selected and typical comments on topics often discussed during focus group or structured interviews on work with man - made vitreous fibres and skin discomfort
this study shows that currently used mmvf products still cause skin discomfort for workers and do - it - yourself consumers . skin irritation caused by mmvf materials
the former hazard classification of mmvfs as skin irritants was removed in 2009 , but without scientific evidence for the change .
the overall aim of the present study was to update and increase our knowledge about the skin effects of mmvf products , focusing on products used in sweden around 2010 . in this study using focus groups and structured interviews , we hoped to receive answers to the following questions :  which current mmvf material or product in use causes the most skin discomfort? ,  what task / working position / situation causes the most skin discomfort? , and  where on the body do you experience discomfort most? in all , 106 participants contributed with their opinions and experience in focus groups and by structured interviews .
the number of focus group participants is quite large as compared with many other focus group studies 2329 .
participants were building construction workers , bricklayers , loose wool insulators , electricians , pipe and ventilation insulators , high - school teachers , and do - it - yourself consumers .
we did not interview workers occupied in disassembling mmvf insulation materials , as this study dealt with current mmvf products . neither did we interview workers at large industrial ventilation companies , workers manufacturing mmvf materials , or people working with other types of glassy ( amorphous and vitreous ) fibres 24 . with regard to the first question , 
which mmvf material or product in use causes the most skin discomfort? , the most common answer or comment was that yellow glass fibre insulation products caused the most skin discomfort ( those available in sweden during 20092010 ) .
the loose wool insulators , who seldom used yellow glass fibre wool , considered the green / grey rock wool to cause more skin discomfort than the newer white glass fibre wool .
yellow glass fibre insulation products were quite uncommon at the time in the two large construction companies engaged , where more of the grey / green rock wool products were used .
yellow glass fibre insulation products were the most frequently displayed products at building materials stores .
white glass fibre wool ( described as  soft as cotton by some of the construction workers ) was used by loose wool insulators only .
we have not found any scientific report supporting or contradicting this statement . in response to the second question ,  what task / working position / situation causes the most skin discomfort? , building construction workers and electricians jointly stated that working with the hands above the head ( insulation of or electrical work in ceilings or narrow lofts ) was the worst scenario , because loose fibrous materials fall down onto the face and body .
bricklayers indicated the same , describing the worst situation as lifting the insulation boards up to the next floor or to the frame .
loose wool insulators indicated no special worst working situation apart from crawling in attics and in narrow lofts . for the third question ,  where on the body
do you experience discomfort most? , the most common answer was on the neck ( inside the collar ) , wrists , forearms , and face , regardless of profession or work task .
this is in agreement with previous studies 7,9,10,14,15 . during discussions about skin effects , inhalation discomfort , which was caused by the dusty environment according to the participants ,
, we asked the participants not to discuss this topic , and we promised to give information about health effects and legislation when the interview was over .
focus group interviews have been used for studying the effects of hazardous fibres , for instance in a study aiming to identify important information gaps concerning asbestos exposure assessments 30 . in a study in libby , montana , united states ,
focus group methods were used in a community experiencing a disaster caused by widespread asbestos exposure 31 . in both medical research and occupational and public health studies ,
focus groups have been used frequently to obtain a variety of information from patients or workers 2326,32,33 .
focus groups have been used in dermatology to obtain data concerning experiences of many conditions , for example pruritus in psoriasis 27 , dermatological treatments 28,29,34 , and hidradenitis 35 .
the moderator in the present study ( c.m . ) had no previous knowledge concerning the technical aspects of the problem ; such knowledge might have helped to improve the questions with an explicit description of the actual working tasks . a technical expert ( l.l . ) participated , and answered questions about fibre characteristics and legislation during and after the formal part of the interview .
could the same answers to the three main questions ( a , b , and c ) be obtained by some other technique ?
the use of simple structured interviews alone would have been possible , but the depth in the answers would have been lost .
we believe that the focus group interviews enhanced the reliability of the outcome , particularly for question a (  which mmvf material or product in use causes the most skin discomfort? ) .
the interview technique allowed follow - up questions and probing of the information given during the interview , for example when uncertainties were raised about the fibrous material discussed .
we also believe that the purposive sampling methods used for recruiting the participants did not influence our findings .
another interesting finding obtained from the interviews was that the majority of participants agreed that warm and sweaty situations enhanced skin discomfort independently of tasks .
explanations may be the wearing of less clothing and less protective equipment , or the fact that wet / moist skin might increase the deposition of fibres on the skin .
the most frequently reported method for removing fibres from the skin after work was to take a shower .
most thought that cold water was better than hot water ,  so that the pores can close and thus stop fibres penetrating ; some thought that hot water  opens the pores and lets the fibres out. however , all claimed that showering does not completely remove fibres .
accounts of severity and duration of the discomfort ranged from slight itching to sleepless nights .
it was not always easy to distinguish opinions and perceptions derived from experiences of currently used materials from those derived from previous exposure to older products .
it was quite clear , however , that those with experience of both new and older materials thought that previous mmvf materials caused more severe skin discomfort .
occasionally , some new and mmvf - free insulation products were mentioned , indicating that some of these also caused skin discomfort .
we did not encourage further discussion on such materials , however , as they were outside the scope of this study .
only pipe / ventilation workers and loose wool insulators were normally exposed to different mmvf fibres on a daily basis .
the other groups were exposed on separate occasions depending on tasks , for up to a few days a month .
electricians and teachers did not themselves work with mmvf materials , but were exposed through others handling them .
it is interesting that building construction apprentices performed insulation tasks more often than senior workers , who , we believe , preferred to avoid these tasks .
they acknowledged the distribution of the work , but also considered the training exercise to be part of their apprenticeship .
protective equipment was generally limited to gloves and long sleeves , depending on room temperature and whether the insulation task was performed indoors or outdoors .
the use of eye protectors was compulsory in one company , but this was viewed with some scepticism by some others .
others assumed they it would be easy to become accustomed to eye protectors , and saw the benefits of not getting fibres in the eyes . in provisions and general recommendations from the swedish work environment authority on synthetic inorganic fibres !
afs 2004:1 37 ] , it is written that  with work generating large quantities of dust , protective clothing shall be used .
this clothing shall cover sensitive areas of skin , e.g. the neck and forarms. also , breathing protectors shall be used  where it is not technically possible to keep the atmospheric concentration of mmvfs at an acceptable level .
the fibre products used by participants in the present study were characterized concerning chemical composition and fibre size [ there is some indication that coarser fibres of mmvf can cause more severe skin discomfort 15 ] .
the products did not differ markedly from what has been reported previously ( supporting information doc.s1 ) .
yellow glass fibre materials normally had slightly higher fibre diameters ( 3.26.4  m ) than fibres made of rock or stone ( 1.73.9  m ) . the new white glass wool used by loose wool insulators had a fibre diameter between 1.9 and 2.3  m , similarly to rock or stone wool . to the best of our knowledge ,
no data concerning changes in the use of fibrous material during recent decades in sweden have been published .
additives may be present in fibrous materials ( antistatic agents , anti - mould agents , anti - dust agents , binders , etc . ) , and their use may have changed over time .
however , the possible influence of additives was outside the scope of this study . in 2009
the old risk phrase r38 ( irritating to the skin ) and the new hazard statement h315 ( causes skin irritation ) were removed .
the decision was not unanimous , and some member states recommended that the classification should be maintained ( on the basis of studies published between 1950 and 1980 ) .
one reason for the present study was to generate new knowledge , so that classification and labelling can be based on currently used mmvf materials .
a high - school construction programme teacher gave the opinion that female students performed the insulation task  more accurately and better. he also mentioned that they carried the insulation boards further away from the body than male students , who often carried more boards and were thus in closer contact with them .
the authors perceptions from the interviews were that workers and consumers own knowledge on possible skin effects of mmvf fibres was quite low .
this often led to speculations and unfounded ideas about risks associated with the materials , as well as notions of mechanisms and treatment .
our study shows that mmvf materials still cause skin discomfort for workers and do - it - yourself consumers . on the basis of the outcome of this study ,
a controlled provocation study with mmvf materials is currently being performed in a human exposure chamber 39,40 .
we suggest that updated knowledge about skin discomfort and other skin effects resulting from work with mmvf materials should be taken seriously , and should possibly result in a renewal of their classification and labelling as skin irritants .
additional supporting information may be found in the online version of this article fibre size and chemical composition of some current insulation mmvf products in sweden .
 backgroundman - made vitreous fibres ( mmvfs ) are used in products for insulation and as reinforcement in materials . 
 contamination of the skin may arise through direct or indirect contact , and from the deposition of airborne fibres . 
 the scientific basis regarding the effects on skin of mmvfs dates from 19701980.objectivesto investigate whether currently used insulation mmvf products still cause skin discomfort.methodsfocus group interviews and structured interviews were performed among workers engaged in insulation tasks and among do - it - yourself consumers with a recent experience of mmvf products.resultsa majority of interviewees experienced skin discomfort when handling mmvf products . 
 complaints caused by traditional ( yellow ) glass fibre products were more severe than those caused by products of rock or slag wool fibres . 
 the wrists , forearms , neck and face were the locations where the skin was most affected . 
 the situations causing problems varied between occupational tasks , but working with the hands over the head or in narrow spaces were described as the worst situations . 
 building construction apprentices performed insulation tasks more often than senior workers.conclusionsmmvf insulation products do still cause skin discomfort . 
 updated knowledge about people s experiences of work with such products should influence legislation . 
Methods
Participants
Interviews
Pilot structured interview
Focus group interviews
Structured interviews
Other sources of information
Questions and topics in focus groups and structured interviews
Results
Discussion
Supporting Information