### This document is in the public domain and may be freely copied or reprinted.
DISCLAIMER Mention of any company or product does not constitute endorsement by the National Institute for Occupational Safety and Health (NIOSH). In addition, citations to Web sites external to NIOSH do not constitute NIOSH endorsement of the sponsoring organizations or their programs or products. Furthermore, NIOSH is not responsible for the content of these Web sites. 

### ORDERING INFORMATION To receive documents or other information about occupational safety and health topics, contact NIOSH at NIOSH—Publications Dissemination 4676 Columbia Parkway Cincinnati, OH 45226–1998 Telephone: 1–800–35–NIOSH (1–800–356–4674) Fax: 513–533–8573 E-mail: pubstaft@cdc.gov or visit the NIOSH Web site at www.cdc.gov/niosh DHHS (NIOSH) Publication No. 2006–149 September 2006



### SAFER • HEALTHIER • PEOPLE TM

# Preventing Asthma and Death from MDI * 

# Exposure During Spray-on Truck Bed Liner and Related Applications

WARNING! Workers exposed to MDI may develop serious or fatal respiratory disease. 

# W orkers should take the following steps to protect themselves from MDI * expo sure during spray-on applications: 1. Be informed. ■ Participate

- ing, training ■ Know

- low

- facturers 2. Use respirators and PPE safely. ■ Make respirators their ■ Regularly parts respirators

- ness. hoses, ■ When always

- pirator other wear - ment chemical-resistant ■ Never face

- tic visibility ■ Be occur ■ After

- moving

- tilation MDI. ■ Do has

- mum a - ganic ■ Know purifying the

- quately —

—

* MDI 3. Check the ventilation system in the spray enclosure. ■ Make	sure	that	the	s pray	enclosure	ventilation	is operating	correctly	before	beg inning	the	spray	process. ■ Ensure	that	ventilatio n	system	intake	filters	are	not clogged	and	are	correctl y	installed	in	their	frames. ■ Keep	the	ventilation	system	running	until	the	MDIaerosol	has	been	cleared	from	the	spray	enclosure. 4. Use good work practices and personal hygiene. ■ Never	eat	or	drink	in	work	areas. ■ Wash	hands	and	face	before	eating,	drinking,	or smoking. 5. Report symptoms. ■ Do	the	following	if	you	have	symptoms: Tell	your	employer	if	you	develop	breathingproblems	that	could	be	related	to	MDI	exposure	 (wheezing,	 chest	 tightness,	 shortness of	breath,	or	coughing). S eek	m edi c al ev a l u a t i o n of	those	symptoms.Do	not	spray	or	remain	exposed	to	MDI	until	you	are	medically	evaluated	for	breathing problems	that	might	be	related	to	the	spray

ing process. ■ If	 you	 have	 been	 diagnosed	 with	 occupational asthma	 due	 to	 sensitization	 from	 MDI,	 do	 not work	where	you	might	be	exposed	to	MDI. —

—

— Spraying base coat with protective equipment.

For additional information, see NIOSH Alert: Prevent ing Asthma and Death from MDI Exposure During Spray-on Truck Bed Liner and Related Applications [DHHS (NIOSH) Publication No. 2006–149]. Single cop ies of the Alert are available free from the following: NIOSH—Publications Dissemination 4676 Columbia Parkway Cincinnati, OH 45226–1998 Telephone: 1–800–35–NIOSH (1–800–356–4674) Fax: 1–513–533–8573 ■ E-mail: pubstaft@cdc.gov or visit the NIOSH Web site at www.cdc.gov/niosh

DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Institute for Occupational Safety and Health

# Preventing Asthma and Death from MDI * 

# Exposure During Spray-on Truck Bed and Related Applications L

d m

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-air	resand	 orequipoveralls, ear). rom	thear	plase	better
trations
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### WARNING! Workers exposed to MDI may develop serious or fatal respiratory disease. 

# W orkers should take the following steps to protect themselves from MDI * expo sure during spray-on applications: 1. Be informed. ■ Participate in medical exams, medical monitor

ing, air monitoring, respiratory fit-testing, and training programs offered by your employer. ■ Know the safety and health information and fol

low all safety precautions provided by the manu facturers about the product(s) you are spraying. 2. Use respirators and PPE safely. ■ Make sure that you have been fit-tested for your respirators and that you have been trained in their proper use, storage, and maintenance. ■ Regularly inspect and maintain all component parts of supplied-air respirators and air-purifying respirators to assure their continued effective

ness. The components include air compressors, hoses, regulators, facepiece, etc. ■ When	spraying	MDI, always	use	a	full-facepiece,	supplie pirator	 operated	 in	 a	 pressure-de other	positive-pressure	mode	and wear	appropriate	personal	protectiv ment	 (PPE)	 (such	 as	 hooded chemical-resistant	gloves,	and	foot ■ Never	remove	or	lift	the	respirator	away face	while	in	the	spray	enclosure.	Use	c tic	tear-away	sheets	on	the	visor	to	provi visibility	throughout	the	spray	process. ■ Be	 aware	 that	 the	 highest	 MDI	 conce occur	inside the spray enclosure. ■ After spraying, leave the sp ray enclosure moving your respira t or and PPE and keep tilation system running t o e xhaust any r MDI. ■ Do not re-enter the spray en closure afte has stopped without P P E and a respira mum protection is an air-p u rifying respi a full facepiece equipp e d with a combin ganic vapor/N95 filter car t ridge). ■ Know the change-o ut schedule for purifying respirator cartridge and stric the schedule to make sure that you quately protected from exposure to MD —

—

* MDI is methylenebis(phenyl isocyanate). In this fact

sheet, MDI refers to all MDI-based isocyanates. 3. Check the ventilation system in the spray enclosure. ■ Make sure that the spray enclosure ventilation is operating correctly before beginning the spray pro cess. ■ Ensure that ventilation system intake filters are not clogged and are correctly installed in their frames. ■ Keep the ventilation system running until the MDI aerosol has been cleared from the spray enclo

sure. 4. Use good work practices and personal hygiene. ■ Never eat or drink in work areas. ■ Wash hands and face before eating, drinking, or smoking. 5. Report symptoms. ■ Do the following if you have symptoms: Tell your employer if you develop breathing problems that could be related to MDI expo sure (wheezing, chest tightness, shortness of breath, or coughing). Seek medical evaluation of those symptoms. Do not spray or remain exposed to MDI un til you are medically evaluated for breathing problems that might be related to the spray ing process. ■ If you have been diagnosed with occupational asthma due to sensitization from MDI, do not work where you might be exposed to MDI. —

—

— Spraying base coat with protective equipment.

For additional information, see NIOSH Alert: Prevent ing Asthma and Death from MDI Exposure During Spray-on Truck Bed Liner and Related Applications [DHHS (NIOSH) Publication No. 2006–149]. Single cop ies of the Alert are available free from the following: NIOSH—Publications Dissemination 4676 Columbia Parkway Cincinnati, OH 45226–1998 Telephone: 1–800–35–NIOSH (1–800–356–4674) Fax: 1–513–533–8573 ■ E-mail: pubstaft@cdc.gov or visit the NIOSH Web site at www.cdc.gov/niosh

DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Institute for Occupational Safety and HealthFor additional information, see N IOSH Alert: Prevent ing Asthma and Death from MDI Exposure During Spray-on Truck Bed Liner and Related Applications [DHHS (NIOSH) Publication No. 2006–149]. Single cop

ies of the Alert are available free from the following: NIOSH—Publications Dissemination 4676 Columbia Parkway Cincinnati, OH 45226–1998 Telephone: 1–800–35–NIOSH (1–800–356–4674) Fax: 1–513–533–8573 ■ E-mail: pubstaft@cdc.gov or visit the NIOSH Web site at www.cdc.gov/niosh

DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Institute for Occupational Safety and Health 

# E mployers should take the following steps to protect workers from MDI expo sure during spray-on applications : 1. Provide workers who may be exposed to MDI with information and training about MDI as required by the OSHA haz ard communication standard [29 CFR † 1910.1200]. ■ Inform workers about the serious health effects that may result from exposure to MDI and pro

vide them with safety and health information. ■ Inform workers about any materials that may contain or be contaminated with MDI. 2. Provide respiratory protection and per sonal protective equipment to workers who may be exposed to MDI. ■ Develop, implement, and enforce a worksitespecific respiratory protection program that pro

vides for medical monitoring, medical examina

tions, respirator fit-testing, and respirator training.

* MDI is methylenebis(phenyl isocyonate). In this fact sheet, MDI refers to all MDI-based isocyanates. † Code of Federal Regulations. ■ Provide appropriate PPE (hooded coveralls, chemical -resistant gloves, and footwear) to work

ers who use spray guns and to other workers who may be exposed to MDI. ■ Train workers to properly use, store, and main

tain their respirators. ■ Regularly inspect and maintain all component parts of supplied-air and air-pu rifying respirators to assure their continued effectiveness. The com

ponents include air compressors, hoses, regula

tors, facepieces, etc. ■ Make sure respirators are professionally fitted
. ■ When workers must wear prescription eye glass

es under a full-facepiece respirator, provide them with prescription inserts designed to be compat

ible with the respirator. Supplied-air respirators ■ When workers are spraying MDI or are inside the spray enclosure during spraying, make sure they use full-facepiece, supplied-air respirators operated in a pressure-demand or other positive-pressure mode. ■ Make sure that supply air for the supplied-air respirator is taken from a clean, uncontaminated area that is well removed from any aerosolized MDI or other contaminants. A ■

ir-purifyin When wo

enclosure facepiece combinati is minimu tions. Establish

for air-pur . Provide Build a sp

ventilatio isolat facilit main sure the s Determin

provided informati spraying) below th (REL). Make sur

neering c effective mize MDI Allow onl

proved, f enter the Establish

nance pr . Provide surveill posed t Provide

and perio —

— ■

3 ■

■

■

■

■
4

■ ,

t

o
e

o g respirators rker s must enter or re-enter the spray after spraying, make sure they use full- air-purifying respirators equipped with a on organic vapor/N95 filter cartridge. Thism acceptable protection for these condiand implement a change-out schedule ifying respirator cartridges. engineering controls. ray enclosure equipped with an exhaust n system to e the spray process from the rest of the y andain the enclosure under negative presto control and contain MDI aerosols in pray enclosure. e the number of air changes per hour by the ventilation system and use this n to calculate the time required (after to reduce airborne MDI concentrations NIOSH recommended exposure limit e that workers are trained to use engiontrols (such as spray enclosures withventilation) and work practices to miniexposures. y t r ained workers wearing NIOSH-apull-facepiece, supplied-air respirators to spray enclosure during spraying. and implement a preventive maintegram for the ventilation system. medical examinations andance for workers potentially exo MDI. a preplacement medical examination dic medical monitoring for all potentially 

# Preventing Asthma and Death from MDI * 

# Exposure During Spray-on Truck Bed Liner and R elated Applications

WARNING! Workers exposed to MDI may develop serious or fatal respiratory disease. exposed workers to detect and prevent the acute and chronic effects of MDI exposure
. ■ Remove from the workplace any worker showing signs or symptoms of MDI exposure. ■ Make sure the worker is medically evaluated be

fore he or she is allowed to return to work. ■ If the medical evaluation determines that the worker is sensitized, the worker must not be al

lowed to return to a job where MDI is used.

Truck in bed liner spray enclosure.For additional information, see NIOSH Alert: Prevent ing Asthma and Death from MDI Exposure During Spray-on Truck Bed Liner and Related Applications [DHHS (NIOSH) Publication No. 2006–149]. Single cop

ies of the Alert are available free from the following: NIOSH—Publications Dissemination 4676 Columbia Parkway Cincinnati, OH 45226–1998 Telephone: 1–800–35–NIOSH (1–800–356–4674) Fax: 1–513–533–8573 ■ E-mail: pubstaft@cdc.gov or visit the NIOSH Web site at www.cdc.gov/niosh

DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Institute for Occupational Safety and Health 

# E mployers should take the following steps to protect workers from MDI expo sure during spray-on applications : 1. Provide workers who may be exposed to MDI with information and training about MDI as required by the OSHA haz ard communication standard [29 CFR † 1910.1200]. ■ Inform workers about the serious health effects that may result from exposure to MDI and pro

vide them with safety and health information. ■ Inform workers about any materials that may contain or be contaminated with MDI. 2. Provide respiratory protection and per sonal protective equipment to workers who may be exposed to MDI. ■ Develop, implement, and enforce a worksitespecific respiratory protection program that pro

vides for medical monitoring, medical examina

tions, respirator fit-testing, and respirator training.

* MDI is methylenebis(phenyl isocyonate). In this fact sheet, MDI refers to all MDI-based isocyanates. † Code of Federal Regulations. ■ Provide appropriate PPE (hooded chemical-resistant gloves, and footwe ers who use spray guns and to other w may be exposed to MDI. ■ coveralls,ar) to workorkers who
and mainomponent respirators

. The comes, regula-
fitted.eye glassovide them e compat-

inside the re they use erated in a ure mode. upplied-air ntaminated aerosolized 

# Line

Train workers to properly use, store, tain their respirators. ■ Regularly inspect and maintain all c parts of supplied-air and air-purifying to assure their continued effectiveness ponents include air compressors, hos tors, facepieces, etc. ■ Make sure respirators are professionally ■ When workers must wear prescription es under a full-facepiece respirator, pr with prescription inserts designed to b ible with the respirator. Supplied-air respirators ■ When workers are spraying MDI or are spray enclosure during spraying, make su full-facepiece, supplied-air respirators op pressure-demand or other positive-press ■ Make sure that supply air for the s respirator is taken from a clean, unco area that is well removed from any MDI or other contaminants. Air-purifying respirators ■ When workers must enter or re-enter the sprayenclosure after spraying, make sure they use fullfacepiece, air-purifying respirators equipped with a combination organic vapor/N95 filter cartridge. This is minimum acceptable protection for these condi

tions
. ■ Establish and implement a change-out schedule for air-purifying respirator cartridges. 3. Provide engineering controls. ■ Build a spray enclosure equipped with an exhaust ventilation system to isolate the spray process from the rest of the facility and maintain the enclosure under negative pres

sure to control and contain MDI aerosols in the spray enclosure. ■ Determine the number of air changes per hour provided by the ventilation system and use this information to calculate the time required (after spraying) to reduce airborne MDI concentrations below the NIOSH recommended exposure limit (REL). ■ Make sure that workers are trained to use engi

neering controls (such as spray enclosures with effective ventilation) and work practices to mini

mize MDI exposures. ■ Allow only trained workers wearing NIOSH approved, full-facepiece, supplied-air respirators to enter the spray enclosure during spraying. ■ Establish and implement a preventive mainte

nance program for the ventilation system. 4. Provide medical examinations and surveillance for workers potentially ex posed to MDI. ■ Provide a preplacement medical examination and periodic medical monitoring for all potentially —

— 

# Preventing Asthma and Death from MDI * 

# Exposure During Spray-on Truck Bed r and Related Applications

WARNING! Workers exposed to MDI may develop serious or fatal respiratory disease. exposed workers to detect and prevent the acute and chronic effects of MDI exposure
. ■ Remove from the workplace any worker showing signs or symptoms of MDI exposure. ■ Make sure the worker is medically evaluated be

fore he or she is allowed to return to work. ■ If the medical evaluation determines that the worker is sensitized, the worker must not be al

lowed to return to a job where MDI is used.

Truck in bed liner spray enclosure.

# Preventing Asthma and Death from MDI * 

# Exposure During Spray-on Truck Bed Liner and Related Applications

spray-on and related applications. Your as

sistance will help prevent asthma, other re

spiratory disease, and death.



### BACKGROUND Spray-on polyurethane/polyurea products containing isocyanates such as MDI have been developed for a wide range of retail, commercial, and industrial uses to protect cement, wood, fiberglass, steel, and alumi

num surfaces such as truck beds, trailers, boats, foundations, and decks. MDI, toluene diisocyanate (TDI), and the polyisocyanate products based on the diisocyanate hexa

methylene diisocyanate (HDI) are the most commonly used diisocyanates in the poly

urethane industry. Isocyanates are widely used in the manufacture of flexible and rigid foams, fibers, coatings such as paints and varnishes, and elastomers. Isocyanates are increasingly used in the automobile industry, autobody repair, and building insulation ma

terials. (See Appendix A for definitions and synonyms of MDI and information about its chemical structure.) 

### WARNING! Workers exposed to MDI * may develop serious or fatal respiratory disease.

The National Institute for Occupational Safety and Health (NIOSH) requests as sistance in preventing asthma, other respiratory diseases, and death from exposure to methylenebis(phenyl iso cyanate) (MDI). More than 10,000 U.S. workers are potentially exposed to MDI during spray-on truck bed lining opera tions. This Alert summarizes four case reports: one death and several incidents of asthma or other respiratory diseasefollowing exposure to MDI during sprayon truck bed lining operations. Informa tion about preventing adverse health ef fects from exposure to MDI is urgently needed by workers, employers, small business owners, and physicians and other health care providers. NIOSH requests that editors of trade jour

nals, safety and health officials, labor union leaders, educators, and MDI suppliers and manufacturers bring the recommendations in this Alert to the attention of all employers and workers at risk of MDI exposure through

* MDI is methylenebis(phenyl isocyanate). In this alert, MDI refers to all MDI-based isocyanates. MDI Exposure During Spray-on Truck Bed Liner and Related Applications Production and consumption data for the polyurethane industry in the United States and North America are available through the Alliance for the Polyurethanes Industry (API). Their publications End-Use Market Survey on the Polyurethane Industry [API 2003] and Socio-Economic Impact of Poly

urethanes in the United States [API 2004a] provide the following facts:
■ In 2002, the U.S. market for polyure

thane was 5,528 million pounds (87% of the North American market). ■ The manufacture of products such as flex

ible slabstock, flexible molded foams, rig

id foams, coatings, binders, elastomers, adhesives, sealants, reaction injection molding, thermoplastic polyurethanes, and spandex used 212 million pounds of MDI as a raw material and 1.3 billion pounds of polymeric MDI in 2002. ■ About 253,700 workers at 853 locations throughout the United States are em

ployed in transportation industries that use polyurethane. Uses include resistant polyurethane coatings such as truck bed liners and other products such as head

rests, armrests, adhesives, insulation, and other molded components used in vehicle production. Information gathered by a major spray-on truck bed liner company identified 17 com

panies that supply, distribute, and franchise spray-on truck bed lining equipment, mate

rials, and products [Naik 2004]. Nationally, the number of spray-on truck bed liner busi

nesses is estimated to exceed 2,000 [Lof

gren et al. 2003]. Press releases from two of the major truck bed liner companies indicate that the spray-on bed liner industry is rapidly growing. Conservative estimates indicate that more than 10,000 workers are employed in the spray-on bed lining industry nationwide. Inspections by the Washington Industrial Safety and Health Administration (WISHA) of the Washington State Department of La

bor and Industries at 13 spray-on truck bed lining businesses and a review of industrial insurance records found that workers are at risk of developing illnesses associated with diisocyanate exposure [Lofgren et al. 2003]. Seven of the 13 inspected worksites had MDI monomer air concentrations that were greater than the regulatory limit, resulting in regulatory citations. During their preparation of the report on in

spections in Washington State, the authors contacted NIOSH and requested help with developing engineering controls and alerting affected employers and workers through

out the Nation. As a result, NIOSH began a study of the spray-on truck bed lining indus

try. NIOSH conducted walk-through surveys at spray-on truck bed liner facilities in Wash

ington State, Colorado, Ohio, and Kentucky [NIOSH 2003a; Almaguer et al. 2004]. Six sampling surveys were conducted in Ohio and Kentucky. The results of the NIOSH sampling surveys are described later in this document. In 2003, Washington and Michigan actively began alerting the industry in their States of the hazards associated with spraying MDI in truck bed liner applications. In March 2003, WISHA issued a Hazard Alert warning of iso

cyanate exposures related to the spray-on truck bed lining industry [WISHA 2003]. The Michigan Occupational Safety and Health Act News described a fatality that occurredin Michigan during the application of an MDIbased spray-on bed liner to the interior of a van in February 2003 [MIOSHA 2003]. In December 2003, the Michigan Fatality and Control Evaluation (MIFACE) Program issued a report on the death, and the Michigan Oc

cupational Safety and Health AdministrationMDI Exposure During Spray-on Truck Bed Liner and Related Applications (MIOSHA) issued an Alert in January 2004 [MIFACE 2003, MIOSHA 2004]. In February 2004, WISHA issued a Hazard Alert Update briefly discussing the Michigan death and the health hazards associated with expo

sure to isocyanates [WISHA 2004]. This Alert is intended to notify workers and employers in the truck bed lining and relat

ed industries of the adverse health effects associated with exposure to MDI during the application of spray-on truck bed liners. The current Alert also provides preliminary recommendations to reduce worker expo

sures to MDI during the spray-on bed liner process.


### SPRAY-ON TRUCK BED LINING PROCESS The spray

- on truck bed lining process in

volves applying a protective polyurethane or polyurea coating to the bed of pickup trucks or other vehicles and surfaces in a manner similar to undercoating. Bed liners are ap

plied as a two-part resin. Part A is an MDIbased product; part B is usually a polyol or polyamine that reacts with the isocyanate to form a tough, resilient elastomeric surface coating. The MDI-based liners are applied to pickup truck beds and other surfaces to protect them from damage and to provide a nonskid surface. The spray-on application process is usually done in a spray enclo

sure. The spray-on truck bed lining process is commonly performed in spray-on truck bed specialty shops, auto body centers, and auto dealerships (see Figure 1). NIOSH identified two spray-on processes commonly found in the industry [Heitbrink and Almaguer 2003]: one process applies truck bed liners at room temperature and pressures of approximately 50 pounds per square inch (low temperature/low pressure); a second process applies truck bed liners at temperatures above 165 °F and pressures of approximately 1,500 pounds per square inch (high temperature/high pressure). In both processes, the A and B components are pumped separately to the spray gun and mixed at the time of application. The worker uses a hand-held spray gun to ap

ply the rapidly curing product onto the truck bed interior. The shape of the spray pattern is determined by the nozzle shape. To cre

ate a textured, nonslip surface on the bed, a small quantity of the coating is sprayed into the air, allowing the product to settle onto the truck bed. To obtain a bed liner thick

ness of 0.125–0.25 inches (a standard in the industry), approximately 50 pounds of the two-part resin (part A and part B) are sprayed onto the bed and inside walls of a typical pickup truck (see Figure 2). A third type of spray-on process that was not included in the NIOSH sampling sur

veys is the cold-batch, pre-mix process. The information contained in this Alert may apply to this process as well. During this process, isocyanate/resin and catalyst materials are Figure 1. Spraying base coat with protective equipment. MDI Exposure During Spray-on Truck Bed Liner and Related Applications generally mixed in small quantities (quarts or gallons) at room temperature with a high-speed drill. Afterwards, the mixture is poured into a hopper gun and applied at 30–60 pounds per square inch from inside the truck bed. The chemicals used in the cold-batch operations typically contain lessMDI (less than 20%). However, the coldbatch materials contain higher amounts of flammable solvents (toluene and N-butyl acetate) which should have their own expo

sure prevention and ventilation requirements. Cold-batch systems are popular because of the lower startup costs [Krupinski 2005].



### SPRAY APPLICATIONS OTHER THAN TRUCK BED LINING Polyurethane and polyurea coatings are marketed and used for truck trailers, house decks, walls, foundations and sports floor

ing, and they are likely to be used for other applications as well. In many cases, these applications use the same or similar chemi

cals, spray techniques, and equipment as the spray-on truck bed lining process. Be

cause of these similarities, excessive expo

sure to MDI may occur during these related applications, resulting in risk to spray gun users and other nearby workers. Owners and managers of these operations should assess and sample as necessary as well as implement needed controls and work practices, including engineering controls, worksite-specific respiratory protection pro

grams, chemical hazard training, administra

tive controls, and use of personal protective equipment for exposed workers as outlined in this Alert [Lofgren et al. 2003].



### HEALTH EFFECTS OF ISOCYANATES Isocyanates are the leading attributable chemical cause of occupational asthma in the United States and many other industri

alized countries [Tarlo et al. 1997b]. Work

ers with asthma symptoms from isocyanate exposure often continue to have symptoms after exposures have been terminated. Af

fected workers often have to leave their jobs to prevent progression of respiratory symp

toms. The major route of work-related ex

posure to MDI is inhalation of the vapor or aerosol. Because the odor threshold for MDI is many times above the recommended exposure limit (REL), smell should never be relied on as an indication of exposure, nor should the absence of odor be used to indicate safety. MDI can be detected by odor only after dan

gerous concentrations exist, resulting in po

tential overexposure. Exposure may also occur through skin con

tact during the handling of liquid MDI-based products. Work-related exposure normally Figure 2 . Spraying texturizing coat with protective equipment.MDI Exposure During Spray-on Truck Bed Liner and Related Applicationsoccurs during the spray application of MDIbased products. In 1996, NIOSH issued Preventing Asthma and Death from Isocya

nate Exposure, which summarizes reported cases of disease and death following occu

pational exposure to diisocyanates and di

isocyanate-based products [NIOSH 1996]. 

### Irritation and Lung Injury MDI and other isocyanates may irritate the mucous membranes of the eyes, upper and lower respiratory tracts, gastrointestinal tract, and skin [Swensson et al. 1955; Fisher 1967; Upjohn Company 1970; Lofgren et al. 2003]. Eye tearing, nose and throat ir

ritation, and cough may occur [Littorin et al. 2000]. Respiratory irritation may progress to chronic upper and lower respiratory symp

toms, although symptoms of local irritation do not reliably indicate chronic respiratory conditions [Wang and Petsonk 2004]. Acute respiratory distress syndrome or reactive air

ways dysfunction syndrome may also result from short-term high exposures [Tarlo et al. 1997b; Banks 1998]. 

### Respiratory Sensitization Isocyanates can sensitize workers, making them subject to severe asthma attacks if they are exposed again, even when concen

trations are continuously below the NIOSH REL [NIOSH 1973, 1978; Banks 1998]. Skin exposures may be associated with the onset of respiratory symptoms [Petsonk et al. 2000]. Respiratory disorders associated with isocyanate exposure include asthma and hypersensitivity pneumonitis [Baur et al. 1984; Baur 1995]. Sensitization may result from a single episode of overexposure or intermittent exposures at low concentra

tions. Once a worker is sensitized, even low concentrations may trigger symptoms such as wheezing, chest tightness, shortness of breath, and cough. Persons with chronic hypersensitivity pneumonitis may also ex

perience fatigue and weight loss. These symptoms may begin immediately or may be delayed for up to 8 hours after exposure. Death from severe asthma in sensitized sub

jects has been reported [Fabbri et al. 1988; MIFACE 2003]. 

### Carcinogenicity Isocyanates may cause cancer in animals; however, evidence is insufficient to describe the carcinogenic potential of MDI in hu

mans. Data from recent studies show that methylene dianiline (MDA), a known animal carcinogen and the principal metabolite ofMDI monomer, is found in the blood of MDIexposed rats and in the urine of humans exposed to a mixture of polymeric MDI and MDI monomer [NIOSH 1986; Sepai et al. 1995]. Another study found that a commer

cial grade of MDI (45% MDI monomer by weight) induced chromosome aberrations in human blood lymphocyte cultures after a 24-hour treatment [Mäki-Paakkenen and Norppa 1987]. NIOSH recommends that work-related exposure to MDI be minimized because of the potential for respiratory sen

sitization and the potential carcinogenicity of the metabolite MDA [NIOSH 1986].



### CURRENT EXPOSURE LIMITS Occupational exposure standards for MDI are based on respiratory irritation and sen

sitization. The available human evidence is insufficient to describe the carcinogenic potential of MDI [NIOSH 1989]. The evolu

tion of the occupational exposure standards for isocyanates is discussed in the litera

ture review Polyisocyanates in Occupational MDI Exposure During Spray-on Truck Bed Liner and Related Applications Environments: A Critical Review of Expo

sure Limits and Metrics [Bello et al. 2004]. The isocyanate product frequently used in bed-liner formulations consists of varying amounts of MDI monomer and higher mo

lecular weight species. Long-term aerosol inhalation studies suggest that monomeric MDI and polymeric MDI, which typically con

tain 50% monomer, have a similar response in rat lungs [Feron et al. 2001]. Mandatory and recommended limits have been estab

lished for MDI monomer, as discussed be

low . However, no recommended or regu

latory limit exists for higher molecular weight species at this time. Therefore, regardless of the relative amount of MDI monomer pres

ent, owners and workers are encouraged to adhere to the control methods outlined in this Alert whenever MDI aerosols may be generated through a spray-on bed-lining op

eration. 

### NIOSH NIOSH recommends that MDI monomer ex

posure be limited to 0.05 milligram per cu

bic meter of air (mg/m 3 ) or 0.005 part per million parts of air ( 0.005 ppm) as a timeweighted average (TWA) for up to a 10-hour workday during a 40-hour workweek, with a ceiling limit of 0.2 mg/m 3 (0.02 ppm) for any 10-minute period [NIOSH 1978]. This NIOSH REL is intended to prevent acute and chronic irritation and sensitization of workers but not to prevent health effects in workers who are already sensitized. Avail

able data do not indicate a concentration at which MDI fails to produce adverse re

actions in sensitized persons. Unless oth

erwise stated, use of the term NIOSH REL in this document means the NIOSH REL of 0.2 mg/m 3 as a 10-minute ceiling concen

tration when referring to spray-on truck bed liner processes. 

### OSHA The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for MDI monomer is 0.2 mg/m 3 as a ceiling limit (0.02 ppm) [29 CFR * 1910.1000 (a)(1)].



### WORKPLACE EXPOSURE ASSESSMENTS Washington State In response to health concerns, Washington Industrial Safety and Health Administration (WISHA) inspectors conducted exposure as

sessments at 13 spray-on bedliner estab

lishments [Lofgren et al. 2003]. Airborne concentrations of MDI monomer during the 10- to 20-minute application process varied between shops and ranged from 0.045 to 6.5 mg/m 3 . In 7 of the 13 shops, airborne concentrations of MDI monomer exceeded the State and OSHA ceiling limit of 0.2 mg/m 3

. The method used for most samples consist

ed of an open-faced cassette having a filter treated with 1-(2-pyridyl) piperazine. WISHA concluded that conditions contributing to excess exposure included inadequate ex

haust and make-up air, clogged ventilation filters, and a lack of training and awareness of the hazard. Workers who applied spray used either a supplied-air respirator or an air-purifying respirator with filter cartridge. Companies were cited for deficient respi

rators, inadequate respirator training pro

grams, and lack of respirator fit-testing and engineering controls. Seven of the worksites with overexposure to MDI had one or more serious violations related to respirator use.

* Code of Federal Regulations. See CFR in referenc es. MDI Exposure During Spray-on Truck Bed Liner and Related Applications In addition, one establishment using a bed

liner product containing a flammable sol

vent received a violation for the presence of sources of ignition in the spray area.


### NIOSH The following summarizes MDI monomer exposure assessments from NIOSH surveys conducted at six spray-on truck bed liner sites. These exposure assessment sites in

cluded three surveys at low-temperature/ low-pressure operations and three surveys at high-temperature/high-pressure opera

tions. Samples were collected in the spray enclosures during the bedliner applica

tion process, in truck preparation areas, in the office areas, and outdoors as close as practicable to the spray enclosure exhaust grill. Sampling was done for the duration of the process, which ranged from 16 to 43minutes in the spray enclosure. Longerduration sampling was done in areas outside the spray enclosure. The air samples were collected and analyzed using NIOSH Method 5525 [isocyanates, total (MAP)], which uses 1-(9-anthracenylmethyl)-piperazine (MAP) as the derivatizing reagent [NIOSH 2003b]. In accordance with the recommendations in NIOSH Method 5525 for sampling MDI aero

sols, an impinger with MAP reagent solution followed by a MAP reagent-coated filter was used for collecting the air sample. The labo

ratory analysis of samples used high-perfor

mance liquid chromotography with ultravio

let absorbance/fluorescence detection. Spray Enclosure The data from these six surveys show that the greatest risk for exposure occurs, as expect

ed, in the spray enclosure. Airborne concen

trations of MDI monomer were up to 27 times the NIOSH REL of 0.2 mg/m 3 as a 10-minute ceiling concentration in the spray enclosure during the spray-on process. The geometric mean MDI monomer concentration in the spray enclosures at the low-temperature/ low-pressure process was 0.99 mg/m 3 , or approximately 5 times the NIOSH REL. The geometric mean MDI monomer concentra

tion in the spray enclosures at the hightemperature/high-pressure process was 0.78 mg/m 3 or approximately 4 times the NIOSH REL. Nonmonomeric MDI was de

tected in the spray enclosure samples and ranged up to 42% of the total isocyanate group. All workers applying spray wore sup

plied-air, full-facepiece respirators, except for one who wore a supplied-air, half-face

piece respirator [Almaguer et al. 2004].After the spray application process, postspray air samples were collected inside the spray enclosure. Eight of 12 post-spray samples showed low concentrations of MDI monomer; 4 of the 12 samples had non

detectable concentrations. These samples were typically 15- to 30-minute samples and ranged from below the limit of detection to 0.08 mg/m 3 . These results are averaged over the duration of the sample; concentra

tions immediately after spray application are expected to be higher and may require respiratory protection when re-entering the booth (usually to remove the vehicle) (see Recommendations ). Truck Preparation Area Airborne MDI monomer in the truck prepa

ration area averaged 0.56% of that in the spray enclosure. Eight of the 12 samples taken in the truck preparation area were below the limit of detection. The four samples above the limit of detection had concentrations that ranged from 0.0057 to 0.022 mg/m 3 . Unlike spray gun users, the workers in the truck preparation areasdid not wear respirators designed to protect from exposure to MDI. The concentrations in the truck preparation area were below the NIOSH REL. However, detecting any MDI in the truck preparation area indicates that the spray enclosure was not under negative pressure as recommended. Because of the potential for worker sensitization to MDI, the spray enclosure should be maintained under a negative pressure to minimize the possibil

ity that MDI monomer will escape from the spray enclosure to the truck preparation area or other adjacent work areas, and prevent worker sensitization.
Office Area In five of the six surveys, airborne MDI mono

mer in the office/lobby areas was below the limit of detection. Trace concentrations of MDI monomer (below the limit of quantita

tion) were detected in the office/lobby area of one shop. Again, this finding indicates that the spray enclosure was not under neg

ative pressure as recommended, thereby presenting the potential for exposure to the office occupants. Placing the office/lobby areas as far as possible from the spray en

closure and exhaust areas minimizes pos

sible exposure to MDI in these areas.
Exhaust Area Five of eleven outdoor samples for MDI monomer taken near the spray enclosure exhaust had concentrations greater than the limit of detection; the highest was 0.41 mg/m 3 . These data indicate a poten

tial for exposure to MDI in the exhaust area of the building, requiring restrictions as ad

dressed in the Recommendations
. Observations at the surveyed worksites sug

gest effective exhaust ventilation may have reduced MDI monomer concentrations in the spray enclosure during spray applications [Al

maguer et al. 2004]. Only one site had an exhaust system designed to effectively cap

ture contaiminants in the spray enclosure; at this site, airborne MDI was reduced to con

centrations near the NIOSH REL. Airborne concentrations at 5 other sites with general exhaust ventilation were 3 to 27 times the NIOSH REL.



### CASE REPORTS The following case reports highlight exam

ples of isocyanate-induced asthma, other respiratory disease, and death. 

### Case 1—Spray-on Truck Bed Lining (Fatal Asthma) A 45-year-old male worker with 1 year of tenure died from an acute asthma attack after spraying an MDI-based bed liner onto the floor and sides of a cargo van interior. The worker was wearing a half-mask, sup

plied-air respirator as well as latex gloves and coveralls. The spray area was defined only by “two curtains that could be pulled together to enclose the area and limit prod

uct overspray into the general shop area.” The room had no local exhaust ventila

tion. Room ventilation during the spray-on bedliner application was provided by rais

ing the overhead door a few feet, opening the door near the rust-proofing area, and placing a box fan at this door to provide air circulation. After completing the job, the worker turned off the mixer for the spray-liner components (MDI and polyether polyol). He disconnected his airline from the respirator and walked around to the front of the build

ing, where a coworker found him in acute respiratory distress. The coworker took him to a nearby urgent care facility where he de

veloped cardiac arrest. He did not respond MDI Exposure During Spray-on Truck Bed Liner and Related Applications to cardiopulmonary resuscitation. An ambu

lance took the worker to the local hospital emergency room where he was declared dead. After an autopsy, the county medical examiner stated that the worker had died of an “acute asthmatic reaction due to inhala

tion of chemicals.” In the past, the worker had tried to spray bed liners when customers and cowork

ers were not present because of the strong odors associated with the product. After the fatality, coworkers informed the owner that the victim said he had difficulty breathing after applying the bed liners and that he had used an inhaler. This fatality may have been caused by MDI sensitization. The spray area was enclosed with a curtain (not a permanent enclosure) and had no dedicated exhaust ventilation.The worker used a spray-gun and a halfmask, supplied-air respirator. Furthermore, the MIFACE report indicates that the worker told coworkers that he had had previous breathing difficulties after spraying bed lin

ers and that he had used an inhaler in the past. This suggests that MDI sensitization probably occurred in the past and played a significant part in the fatality. The informa

tion reinforces the need for strict adherence to the recommendations in this Alert. Whether the worker knew that his past breathing problems were associated with his exposures at work was unclear, since he did not report them to the owner. No expo

sure assessment data are available for this fatality [MIFACE 2003; MIOSHA 2004]. 

### Case 2 —Spray-on Truck Bed Lining (Asthma) A 29-year-old male ex-smoker who worked spraying truck bed liners arrived at a hospital emergency room with complaints of chest discomfort and wheezing. He reported hav

ing been exposed to “fumes” generatedduring the application of MDI-based sprayon truck bed liners. He reported increasingly frequent episodes of shortness of breath and wheezing associated with exposure to isocyanates during 8 months of work at the truck bed lining company. The worker was diagnosed with asthma, treated with in

haled bronchodilators and intravenous ste

riods, and advised to see a pulmonologist. The emergency room record indicated that the physician failed to identify the isocya

nate exposure reported by the worker as a possible etiology of the worker’s asthma [Bonauto and Lofgren 2004]. 

### Case 3—Spray-on Truck Bed Lining (Asthma) A 30-year-old man developed rhinitis, a cough, wheezing, and shortness of breath 4 months after starting work spraying truck bed liners. On one occasion, the worker re

ported to the emergency room but was not diagnosed with asthma. Symptoms persisted with daily episodes of shortness of breath, wheezing, and nausea. These symptoms oc

curred at midday after four to five bed liner applications. After 4 months of symptoms, which culminated in hospitalization for re

spiratory distress, the worker was diagnosed with work-related asthma from exposure to MDI. After hospitalization, the worker was documented to have nonspecific bronchial hyperreactivity by methacholine challenge testing. No inhalation challenge with MDI or workplace challenge testing was ever per

formed. The worker was removed from the workplace. One year later, the worker was employed elsewhere as a manual laborer. He still had10 MDI Exposure During Spray-on Truck Bed Liner and Related Applications symptomatic asthma and was maintained on bronchodilators and inhaled steroids [Bonauto and Lofgren 2004]. 

### Case 4 —Spray-on Truck Bed Lining (Asthma) A 22-year-old worker who used a spray gun was employed in the truck bed lining indus

try for 18 months. He developed a runny nose and nasal congestion that occurred during the workweek but improved over the weekend. Increased breathing difficulty on exertion restricted his daily activities. The worker underwent a medical evaluation that included spirometry before and after the administration of bronchodilators. He was documented to have a reversible airflow lim

itation and was diagnosed with asthma. No workplace challenge testing was performed. The material safety data sheets (MSDSs) provided to the medical personnel revealed that the spray-on bed liner material consist

ed of 50% to 60% MDI monomer and 5% to 20% diisooctyl phthalate. The worker was removed from the workplace. A year and a half after medical removal from the workplace, the affected worker was still unemployed. He continued to have symp

tomatic asthma and was maintained on bronchodilators and steroid inhalers [Bon

auto and Lofgren 2004].



### CONCLUSIONS
The cases described in this document reveal the potentially serious nature of respiratory disease resulting from exposures to MDI in the spray-on truck bed liner industry. Expo

sures may increase the risk of serious respi

ratory disease, respiratory sensitization, and death. MDI concentrations generated by the spray-on application of truck bed liners at the NIOSH exposure assessment sites rou

tinely exceeded the NIOSH and OSHA ceil

ing limits and varied throughout the process with unpredictable, rapid increases in air

borne concentrations. On the basis of thesefindings, NIOSH concludes that only a fullfacepiece, supplied-air respirator provides the necessary protection during MDI spray operations.



### RECOMMENDATIONS Manufacturers and distributors of spray-on polyurethane/polyurea products contain

ing MDI and other isocyanates should work together to assess and determine the best controls for the spray-on bed liner process. The ultimate goal is to establish procedures and develop controls (such as proper ven

tilation) to minimize MDI concentrations within the spray enclosures. These proce

dures and controls—together with respi

rator use, a written respiratory protection program, and ongoing worker training—will reduce the risk for worker exposures during the spray-on process. 

### General Responsibilities for Shop Owners and Workers to Prevent MDI Exposures ■ Use any training, information, and litera

ture available through the manufacturers, distributors, franchisers, and government agencies (see examples under manufac

turer responsibilities). ■ Isolate the spray process by building an enclosure equipped with exhaust venti

lation. ■ Use a pressure manometer or tracer smoke along cracks and walls to e n sure that the spray enclosure is under11 MDI Exposure During Spray-on Truck Bed Liner and Related Applications negative pressure and prevents the es

cape of MDI to adjacent work areas. ■ Use a full-facepiece, supplied-air respira

tor and wear personal protective clothingsuch as hooded coveralls, chemicalresistant gloves, and footwear to prevent dermal absorption during the spray ap

plication process. ■ When entering or re-entering the en

closure immediately after spraying, use a full-facepiece, air-purifying respirator equipped with a combination N95 filter/ organic vapor cartridge as minimum pro

tection and wear appropriate clothing to prevent dermal exposure. ■ To prevent fouling of the exhaust system and fan blades, filter all exhaust air at its collection point within the spray enclosure before it enters the exhaust system. ■ Discharge exhaust from the spray enclosure away from occupied areas and ensure that the exhaust outlet is located away from HVAC air sup

ply intakes and supplied-air respirator pumps/compressors. ■ Ensure that only authorized persons trained in the use of safe work prac

tices, ventilation, and personal protec

tive equipment are allowed to perform spraying. 

### General Responsibilities of Manufacturers, Distributors, and Franchisers of Spray-on Chemicals and Equipment
■ Provide safety and health information to users of your chemicals and equipment. Include information about design of spray enclosures, engineering controls, safe work practices, and the hazards of exposure. These two references are ex

cellent examples of useful information:

— MDI and TDI: Safety, Health and the Environment [Allport et al. 2003], by the International Isocyanate Insti

tute Inc. for occupational safety and health information about MDI.

— The API brochure Truck Bed Liners: Worker Protection , available in both English and Spanish. The brochure outlines safety precautions for spray gun users who apply spray-on truck bed liners [API 2004b]. The brochure is available through the API Web site at www.polyurethane.or g . ■ Develop, publish, and distribute addi

tional safety and health resources to help workers using spray-on MDI products. 

### Detailed Recommendations The following sections provide detailed rec

ommendations for this industry, including fur

ther guidance about the choice of respirators and appropriate ventilation parameters. Product Substitution When feasible, substitute a less hazard

ous material for MDI and other isocyanates. NIOSH policy is always to recommend using a less toxic substitute if available. Water-borne acrylic coatings, polysulfide rubber coating, and epoxy are other chemicals that havebeen used to make truck bed liners. Dropin truck bed liners are also commercially available. NIOSH cannot address the quality or performance and has not addressed the safety of these products. In addition, using substitute chemical pro

cesses or products may have advantages and disadvantages, including safety and health issues that are not addressed in this Alert.1 MDI Exposure During Spray-on Truck Bed Liner and Related Applications Equipment/Formulation Modification ■ Manufacturing and distribution: Investi

gate design changes that result in less aerosolization or fewer fugitive emissions during the spray process.
■ Bed liner industry: Investigate potential process changes and work practices to determine whether reduced application pressure and slower application tech

niques result in lower MDI monomer air concentrations during the spray process.
■ Chemical manufacturing: Consider chang

es in chemistry and formulation that would reduce the amount of fugitive MDI released during spraying. These design, process, and formulation chang

es could reduce airborne MDI, resulting in reduced worker exposures. They would also place less financial burden on retail owners and operators in controlling airborne contam

inants during the spray process. Furthermore, less overspray would produce less waste and provide further economic benefit for the retail owner. Unverified evidence from a spray-on bed liner company suggests that using lower pressures (10 pounds per square inch) may reduce airborne MDI concentrations and thus lower the exposure. Spray Enclosure and Ventilation Ventilation design (see Appendix B) ■ Design and build a spray enclosure to isolate the spray process and contain airborne MDI within the enclosure.
■ Minimize the size of enclosure to the smallest floor area and room volume compatible with the operation. This helps to maximize the efficiency of the ventila

tion system. ■ Equip the spray enclosure with an ex

haust ventilation system to capture va

por and particulate MDI near the point of generation.
■ Ensure that the spray enclosure is under negative pressure to prevent leakage of airborne MDI into other areas within the shop.
■ Provide clean “make-up” air to the spray enclosure to replenish exhausted con

taminated air.
■ Place the make-up air supply and exhaust locations of this ventilation system so thatthe system generates a directed air (pushpull type) flow that maximizes ventilation efficiency and contaminant control.
■ Discharge the exhaust high above the roof and away from air intakes, garage doors, or other openings where the ex

haust could re-enter the shop. Also ensure that the exhaust is discharged above the roof recirculation region (See Industrial Ventilation: A Manual of Rec

ommended Practice [ACGIH 2004] to determine the recirculation region).
■ Control access to exhaust discharge areas by physical barriers and warning signs. Work practices Spray gun users should be trained to make their work practices compatible with the control concepts of the ventilation system: ■ Avoid standing between the spray noz

zle and the ventilation system exhaust hood. ■ Work with the spray nozzle downstream of the breathing zone, where the MDI con

taminant will be diluted, directed away13 MDI Exposure During Spray-on Truck Bed Liner and Related Applications from the breathing zone, and less likely to contribute to the worker’s exposure. ■ Allow the exhaust ventilation system to operate for an additional period at the end of spraying operations before deac

tivating the exhaust or allowing person

nel to enter the spray enclosure without proper respiratory protection (see Respi

ratory Protection, page 14). This delay allows the ventilation system to purge or remove most remaining airborne con

taminants. ■ Do not enter exhaust discharge areas without respiratory protection. Ventilation system capabilities ■ Obtain a site-specific exposure assess

ment that includes sampling data at desired intervals following the spray op

eration. These data are the best way to determine the purge time (time required to reduce MDI concentrations consis

tently below the NIOSH REL) required for your ventilation system. ■ In the absence of exposure assessment data, determine the time required for the ventilation system to exhaust an air vol

ume equal to a single room air change. ■ Calculate the required purge time, al

lowing sufficient time for at least three complete air exchanges—or even longer for systems with poor air mixing. ■ During the purge time, use respiratory pro

tection when entering the spray enclosure (see Respiratory Protection, page 14). ■ For assistance calculating the time re

quired for a single air change and the purge time of the ventilation system, see Appendix B. Ventilation maintenance ■ At least once per month, inspect and maintain the ventilation equipment to ensure adequate system performance (or more frequently if a decrease in per

formance is suspected). ■ Document and re-evaluate baseline ven

tilation performance measurements, in

cluding hood static pressure, pressure drop across filters, and velocity or volu

metric flow measurements for indications of system performance degradation. ■ Develop a maintenance schedule to c hange exhaust filters as needed to pre

vent reduced airflow. ■ Ensure that exhaust fans have inspec

tion access doors. ■ Ensure proper filter placement at air ex

haust points to prevent filter bypass and the fouling of the exhaust system. ■ Inspect fan blades regularly for material buildup and clean them to prevent a de

crease in system performance. ■ Check fan belts for deterioration and slippage and replace as necessary. ■ Follow lock-out, tag-out procedures [29 CFR 1910.147] during inspection and maintenance procedures whenever worker injury may result from unexpected start-up of this equipment. Spraying in Enclosed Areas ■ Take a dditional precautions when spray

ing inside vans, enclosed trailers (e.g., horse trailers), and other similarly en

closed spaces. ■ Determine whether the area to be sprayed meets the definition of a confined space and, if so, follow all OSHA requirements1 MDI Exposure During Spray-on Truck Bed Liner and Related Applications for working in a confined space [29 CFR 1910.146]. ■ Use supplemental local exhaust ventila

tion in addition to the exhaust ventilation of the spray enclosure. ■ Wear a full-facepiece, supplied-air res

pirator and appropriate clothing to mini

mize the exposure.
Worker Isolation ■ Restrict access to the spray enclosure to spray gun users. ■ Allow only essential workers wearing ap

propriate respiratory protection into the truck preparation areas or other areas where workers may be exposed to iso

cyanates. Exposure Monitoring ■ If you are a shop owner, conduct an ex

posure assessment for airborne MDI at the onset of business and any time a major change (structural or ventilation) is made to the spray enclosure.

— Even if you install a ventilated en

closure design tested as effective for a product and process, conduct exposure monitoring to verify the ef

fectiveness and proper installation at that site.

— Ensure that spray gun users and the areas adjacent to the spray enclo

sures are sampled.

— Use the appropriate sampling meth

ods, as described in the NIOSH and OSHA analytical methods [NIOSH 2003b, OSHA 1989].
■ Use the NIOSH REL of 0.2 mg/m 3 as a 10-minute or the OSHA PEL of 0.2 mg/m 3 as a 15-minute ceiling limit concentra

tion when interpreting exposure monitor

ing results. The short-term, intermittent nature of the spray-on truck bed liner process makes the NIOSH or OSHA ceil

ing limits the most appropriate exposure criteria for this process. Collect personal breathing zone samples from the time a spray operation begins to the time when spraying has stopped (typically a 10–20 minute period). Compare results with the NIOSH or OSHA ceiling limit. Additional assistance about managing this or other hazards can be obtained from the free, onsite OSHA consultation service in your State. For information about the OSHA Consultation Program, visit www.osha.gov/ dcsp/smallbusiness/consult.htm l or call 1– 800–321–OSHA (1–800–321–6742)
. Respiratory Protection Typically, respirators should not be used as the primary control for routine operations except during situations such as implemen

tation of engineering controls, some shortduration maintenance procedures, and emer

gencies. NIOSH exposure assessment data show that the engineering controls at the NIOSH survey sites did not reduce MDI con

centrations below the occupational criteria, even at the sites with the best ventilation controls [Almaguer et al. 2004] . Airborne MDI monomer concentrations in the spray enclosures during the spray-on application process routinely exceed both the NIOSH 10-minute ceiling limit (0.2 mg/m 3 ) and the OSHA PEL as a 15-minute ceiling concen

tration (0.2 mg/m 3 ). Therefore, NIOSH rec

ommends the following respiratory protec

tion for the spray-on truck bed liner industry. (See Appendix C for more information about respirators and respiratory protection.)15 MDI Exposure During Spray-on Truck Bed Liner and Related Applications Use supplied-air respirators when spraying MDI ■ When spraying MDI-based products (in

cluding spray-on truck bed liners), u se only supplied-air, NIOSH-certified respi

rators [42 CFR 84] with a full facepiece operated in a pressure-demand mode. MDI concentrations generated during the spraying process routinely exceed both the NIOSH and OSHA ceiling limits, even with engineering controls. NIOSH does not recommend air-purifying respi

rators for the spray-on truck bed-liner industry during the spray application,even though OSHA allows the use of airpurifying respirators for isocyanates un

der certain circumstances in accordance with the revised OSHA respiratory protec

tion standard [29 CFR 1910.134(d)(1)(i) and 1910.134(d)(3)(iii)] (see the OSHA Standard Interpretations Letter dated 07/18/2000 and titled Selection of Air Purifying Respirators for Gases and Va

pors with Poor Warning Properties (Diiso

cyanates) [OSHA 2000]). ■ While in the spray enclosure, do not lift or remove the respirator facepiece for any reason. ■ If visibility is a problem during or after spraying, apply several tear-away layers of clear plastic film to the respirator visor before entering the booth. This would al

low the worker to remove the top layer for increased visibility as needed during the spray-on process. Use air-purifying respirators for entry into the enclosure after spraying ■ To enter the spray enclosure after spray

ing is completed, use a full-facepiece, air-purifying respirator with an appropri

ate cartridge changeout schedule that is strictly enforced. NIOSH data indicate that MDI aerosol is still present in the air after spraying. An air-purifying respirator may be the most convenient and practi

cal way to provide protection to workers needing to enter the spray enclosure after the spraying process is complet

ed. A NIOSH-approved, full-facepiece, air-purifying respirator equipped with a combination organic vapor/N95 filter car

tridge is the minimum acceptable protec

tion necessary after spraying is complete and when no exposure assessment data or ventilation purge data are available. ■ Use a full-facepiece to provide the neces sary eye and dermal exposure protection. ■ Because MDI has inadequate warning properties (i.e., odor threshold) and is a potent sensitizer, follow a changeout schedule to ensure that the air-purifying respirator cartridge is replaced before sat

uration of the cartridge elements. Since MDI in this industry is principally an aero

sol, equipping the air-purifying respirator with a particulate pre-filter element to protect the cartridge filter from prema

ture clogging would extend the life of the more expensive filter/cartridge. ■ Before re-entry, allow sufficient time for the ventilation system to remove airborne MDI (see Appendix B to calculate purge time). NIOSH exposure assessments de

termined that three air changes, com

bined with gravitational settling, was suffi

cient to reduce the MDI concentrations to less than 50% of the NIOSH ceiling limit at every sampled site (see Appendix B for details). Develop a respiratory protection program ■ Develop a written, site-specific respira

tory protection program that, at a mini

mum, meets the requirements of the1 MDI Exposure During Spray-on Truck Bed Liner and Related Applications OSHA respiratory protection standard [29 CFR 1910.134] (See Appendix C). ■ Fully implement the respiratory protec

tion program to protect spray gun users and any other workers who enter the spray enclosure. ■ When respirators are needed to protect the health of the worker or when respira

tors are required by the employer, select a NIOSH-certified respirator based on (1) the respiratory hazards to which the worker is exposed and (2) workplace and user factors that affect respirator perfor

mance and reliability [29 CFR 1910.134 (d)(1)(i) and (ii)]. ■ Refer to t he following publications for additional information about selection, fit-testing, use, storage, and cleaning of respiratory equipment:

— NIOSH Guide to Industrial Respira

tory Protection [NIOSH 1987]

— NIOSH Respirator Selection Logic 2004 [NIOSH 2004] www.cdc.gov/ niosh/docs/2005-10 0

— NIOSH Certified Equipment List (CEL). The CEL is a database of all certi

fied respirators. It can be accessed at www.cdc.gov/niosh/npptl/topics/ res pirators/CEL/default.htm l The following links provide additional guid

ance for developing written respiratory pro

tection programs:

— www.osha.gov/SLTC/respiratory protection/index.htm l [OSHA 2004]

— www.polyurethane.org/pdfs/MRPP.pd f [API 2001] Personal Protective Clothing When spraying MDI-based products or dur

ing entry immediately after spraying, wear protective clothing such as hooded coveralls, chemical-resistant gloves, and footwear to protect the skin of the face, scalp, and neck areas from MDI aerosol as recommended in the publications Quick Selection Guide to Chemical Protective Clothing [Forsberg and Mansdorf 2003] and PMDI User Guidelines for Protective Clothing Selection [API 2002] (see Figure 3). Worker and Employer Education Employers Worker education is vital to an effective occu

pational safety and health program. To com

ply with the OSHA hazard communication Figure 3. Worker wearing protective clothing and equipment.1 MDI Exposure During Spray-on Truck Bed Liner and Related Applications standard [29 CFR 1910.1200], inform workers about the following: ■ Methods and observations that may be used to detect the presence or release of a hazardous chemical in the work area (such as monitoring conducted by the employer, continuous monitoring devices, visual appearance or odor of hazardous chemicals when being released, etc.) ■ Physical and health hazards of the chem

icals in the work area, including the likely physical symptoms or effects of over

exposure ■ Protective m easures, such as engineer

ing controls, appropriate work practices, emergency procedures, and personal protective equipment ■ The details of the hazard communica

tion program developed by the employer, including an explanation of the labeling system, the MSDSs, and means for work

ers to obtain and use the appropriate haz

ard information Workers and employers ■ Use this Alert to facilitate chemical haz

ard training for workers spraying MDIbased products, including spray-on truck bed linings. ■ Obtain MSDSs from suppliers or manu

facturers. Chemical manufacturers and distributors ■ Provide customers with information about the health effects of your products, in

cluding MSDSs and labels. ■ Develop safe handling procedures for the chemicals and equipment used in the spraying of MDI-base products. Ensure that the end users are informed of these procedures. ■ Provide easy-to-read information explain

ing the health effects of your products and steps to keep workers safe. Include safe handling brochures such as the API brochure Truck Bed Liner: Worker Protec

tion [API 2004b]. The API brochure is a good example of manufacturers working cooperatively to improve worker safety by communicating important information in an easy-to-read format. Medical Monitoring ■ Conduct preplacement examinations to obtain baseline health status.

— Include all potentially exposed work

ers for the early detection and pre

vention of the acute and chronic ef

fects of exposure to isocyanates.

— Consult an occupational medicine physician who (1) has sufficient train

ing and experience to recognize the adverse health effects of exposure to isocyanates and (2) is aware of the control measures required to de

crease potential worker exposures.

— Include the following in preplacement examinations: 1. A standardized questionnaire that includes detailed medical and work histories with em

phasis on respiratory or aller

gic conditions 2. A physical examination that centers on the respiratory tract 3. Baseline pulmonary function tests (including FEV 1 and FVC). ■ Inform workers who report pre-existing asthma or severe allergies on the preplace

ment examination that it will be difficult to monitor their health status and that if they18 MDI Exposure During Spray-on Truck Bed Liner and Related Applications become sensitized to MDI, their asthma symptoms are likely to worsen. ■ Conduct periodic examinations to up

date medical and work histories every 6 months during the initial 24 months of potential exposure and annually thereaf

ter, with repeat pulmonary function tests every 1 to 2 years.
■ Increase the frequency of the periodic examinations if indicated by the health status of the worker or if there is reason to suspect a lapse in control of isocya

nate exposures.
■ In case of onset or progression of asthmalike symptoms or excessive declines in lung function, arrange for a thorough medical evaluation to determine the presence of asthma.

— If asthma is present, establish the re

lationship to the work environment.

— Ensure that any person who has been medically evaluated and determined to be sensitized to isocyanates (in

cluding MDI) stop all exposure to the implicated agent. Several references are available to guide the evaluation of symptoms in exposed persons[Nicholson et al. 2005; FriedmanJiménez et al. 2000].
■ Record and store information in such a way as to be usable for both the ongo

ing respiratory protection program and to evaluate the distribution of respiratory complaints, patterns of decline in respi

ratory function, or sentinel events.
■ Although respiratory protection programs have a separate function from medical monitoring, information obtained through a respiratory protection program can be incorporated and used as part of an over

all medical surveillance program.
■ Consult published literature for infor

mation about how successful medical monitoring programs are associated with an earlier recognition and improved prognosis for workers who develop occu

pational asthma [Liss et al. 2000; Tarlo et al. 2002, 1997a, 1997b, 1995]. Surveillance and Disease Reporting ■ To enhance the uniformity of reporting work-related asthma, use the report

ing guidelines and asthma surveillance case definition and case classification (see Appendix D). These guidelines and case definition, which have been updated since the 1996 NIOSH Alert, are recom

mended for public health surveillance of work-related asthma reported by physi

cians and other health care providers [NIOSH 1996; Jajosky et al. 1999]. As of 2004, six States—California, Massachu

setts, Michigan, New Jersey, New York, and Washington—are actively engaged in work-related asthma surveillance and preventive activities; one other State— Connecticut—has a work-related asthma surveillance system in place (see Appen

dix E for State contact information for these States). Decontamination and Waste Disposal ■ If you are a manufacturer or distributor, establish procedures for decontamina

tion, waste disposal, and transport for isocyanate-contaminated materials or equipment. Further information about waste disposal is available through local, State, or Federal EPA offices ( www.epa. go v ); the Alliance for the Polyurethanes Industry (API) ( www.polyurethane.or g );1 MDI Exposure During Spray-on Truck Bed Liner and Related Applications and MDI and TDI: Safety, Health and the Environment [Allport 2003].


### FUTURE RESEARCH AND PRODUCTS NIOSH is continuing research on solutions for the spray-on truck bed liner industry in collaboration with other government agencies, academia, and industry repre

sentatives. This research includes the fol

lowing:
■ Investigation of the particle size distri

bution of the overspray and the relative contributions of gravitational settling and ventilation in removing MDI from the at

mosphere of the spray enclosure. ■ Design and evaluation of a negativepressure ventilation system to reduce MDI concentrations within the spray enclosure and to prevent escape of MDI to other areas. ■ Analytical methods research for MDI and other isocyanates. ■ Production and dissemination of a NIOSH Workplace Solutions document detailing ventilation designs and work practices for the spray-on truck bed liner industry.


### ACKNOWLEDGMENTS This Alert was written by Daniel Almaguer, M.S. 1 ; M. Kathleen Ernst 1 ; Lisa G. Benaise, M.D., M.P.H. 2 ; Robert P. Streicher, Ph.D. 1 ; Kenneth R. Mead, M.S., P.E. 1 ; Don J. Lof

gren, C.I.H. 3 ; Dave Bonauto, M.D., M.P.H. 3 ; Alberto Garcia, M.S. 1 ; Roland Berry Ann 1 ; Margaret S. Filios, S.M., R.N. 1 ; and Edward Lee Petsonk, M.D. 1 Stanley A. Shulman, Ph.D., 1 provided sta

tistical support and G. Edward Burroughs, Ph.D., C.I.H., C.S.P., 1 provided guidance and review. Susan Afanuh, Anne C. Hamilton, and Van

essa Becks provided editorial and production services. Please direct comments, questions, or re

quests for additional information to the fol

lowing: Dr. Mary Lynn Woebkenberg Director, Division of Applied Research and Technology National Institute for Occupational Safety and Health 4676 Columbia Parkway Cincinnati, OH 45226–1998 Telephone: 513–533–8462; or call 1–800–35–NIOSH (1–800–356–4674) We greatly appreciate your assistance in protecting the lives of U.S. workers.

John Howard, M.D. Director, National Institute for Occupational Safety and Health Centers for Disease Control and Prevention 1 NIOSH; 2 Centers for Disease Control and Prevention; 3 Washington State Department of Labor and Industries

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cyanate exposure. Olympia, WA: WISHA Ser

vices, Department of Labor and Industries.

# APPENDIX A

Figure 1. MDI Monomer This appendix includes (1) a definition of isocyanates and MDI terms used in the text, (2) a list of commonly used synonyms for MDI monomer, (3) a table of Chemical Ab

stract Service (CAS) numbers associated with MDI, their CAS name and common names or descriptions, and (4) a table of several manufacturers’ MDI-based products used in the truck bed liner industry and their associated CAS numbers.



### ISOCYANATE DEFINITIONS AND CHEMICAL STRUCTURE An isocyanate is any compound that con

tains the -NCO functional group. A func

tional group is any group of atoms that represents a potential reaction site in an organic compound. An isocyanate thus has a nitrogen (N), carbon (C), and oxygen (O) bonded together in such a way as to cre

ate a reactive site within the molecule. In this document, the term diisocyanate re

fers to a chemical compound that contains two isocyanate groups (NCO) per molecule. When specifically referring to the diisocya

nate methylenebis(phenyl isocyanate), the term MDI monomer will be used. The MDI monomer is depicted in Figure 1. The term MDI refers to a mixture containing any com

bination of MDI monomer, MDI prepolymer, or polymeric MDI. The spray-on truck bed liner industry uses MDI-based products as one component of a two component spray-on process. Com

ponent A typically contains a mixture of MDI monomer(s) and modified MDI. All have re

active isocyanate groups present and should be considered possible health hazards.26 MDI Exposure During Spray-on Truck Bed Liner and Related Applications 

### Methylenebis(phenyl isocyanate) Synonyms MDI 1,1-Methylenebis(4-isocyanatobenzene) 4,4’-Diisocyanatodiphenylmethane 4,4’-Diphenylmethane diisocyanate 4,4’-Methylenebis(phenyl isocyanate) 4,4’-Methylenediphenyl diisocyanate Bis(1,4-isocyanatophenyl)methane Bis(4-isocyanatophenyl)methane Diphenylmethane 4,4’-diisocyanate Diphenylmethane diisocyanate Methylenebis(4-isocyanatobenzene) Methylenebis(4-phenylene isocyanate) Methylenebis(phenyl isocyanate) Methylene-di-p-phenylene isocyanate Methylene di(phenylene isocyanate) Methylene bisphenyl isocyanate (Chemical name used in OSHA documents.) Sources: Lewis [1993], NIOSH [1995], Sax and Lewis [1987].27 MDI Exposure During Spray-on Truck Bed Liner and Related Applications Table 1. CAS numbers associated with MDI *
CAS number CAS preferred name Description/ common names 101–68–8 benzene, 1,1’-methylenebis[4-isocyanato- 4,4’-MDI isomer, pure MDI 5873–54–1 benzene, 1-isocyanato-2-[(4-isocyanatophenyl) methyl]- 2,4’-MDI isomer

2536–05–2 benzene, 1,1’-methylenebis[2-isocyanato- 2,2’-MDI isomer 26447–40–5 benzene, 1,1’-methylenebis[isocyanato- MDI (generic), mixture of isomers 9016–87–9 isocyanic acid, polymethylenepolyphenylene ester PMDI, polymeric MDI (generic), mixture of chemical homologues made from the phosgenation of the reaction product of aniline and formaldehyde 25686–28–6 benzene, 1,1’-methylenebis[4-isocyanato-, homopolymer Main components of polymeric MDI, mixture of chemical homo

logues derived from the 4,4’- MDI isomer 17589–24–1 1,3-diazetidine-2,4-dione, 1,3-bis[4- [(4-isocyanatophenyl) methyl]phenyl]- 4,4’-MDI dimer, self-reaction product 31107–36–5 1,3-diazetidin-2-one, 1,3-bis[4-[(4- isocyanatophenyl) methyl]phenyl]-4-[[4- [(4-isocyanatophenyl)methyl]phenyl]imino]- Uretonimine of 4,4’-MDI, a modified MDI (variant) made from self-reaction of 4,4’-MDI at high temperatures 39310–05–9 benzene, 1,1’-methylenebis[isocyanato-, homopolymer Generic polymeric MDI, mixture of chemical homologues derived from the mixture of MDI isomers Source: Allport et al. [2003].

* This list is not all inclusive.Table 2 . CAS numbers associated with specific MDI products † Company CAS number Description The Dow Chemical Company 26447–40–5 5 MDI products support the TBL business. All but one contains MDI prepolymers, which generally do call out the MDI prepolymer CAS number on the MSDS. Bayer MaterialScience 39420–98–9 Bayer systems that are sold into the TBL indus

try are identified as Baytec SPR 085A and Bay

tec SPR 092A. Component A of each of these systems contains the MDI-based isocyanate. Rhino Lining 26447–40–5 101–68–8 9016–87–9 The first two CAS numbers are for commercial Tuff Stuff A Side. The last CAS number is for PMDI (Durabond A Side) Line-X Corporation 26447–40–5 Huntsman Polyurethanes
101–68–8

101–68–8

26447–40–5 39420–98–9

101–68–8 (not disclosed)

101–68–8 (not disclosed)

101–68–8 (not disclosed) MDI product name/Chemical name(s) RUBINATE ® 8001/ 4,4’-Diphenylmethane Diisocyanate RUBINATE ® 1209/ 4,4’-Diphenylmethane Diisocyanate RUBINATE ® 9465/ Generic Diphenylmethane Diisocyanate Modified MDI RUBINATE ® 9495/ 4,4’-Diphenylmethane Diisocyanate Modified MDI RUBINATE ® 9009/ 4,4’-Diphenylmethane Diisocyanate Modified MDI SUPRASEC ® 9537/ 4,4’-Diphenylmethane Diisocyanate Modified MDI Source: API † This list is not all inclusive.

# APPENDIX B

SPRAY ENCLOSURE/VENTILATION DESIGN CONSIDER ATIONS This Appendix contains information about spray enclosure and ventilation design, in

cluding how to determine the number of air changes per hour and calculate the mini

mum required purge time. When substitution is not feasible, engineer

ing controls should be the primary method for reducing airborne isocyanates in the workplace. Spray enclosures should incor

porate exhaust ventilation systems designed to contain, capture and remove vapors and particulates. It is generally advisable to minimize the size and volume of the spray area while seeking to increase the exhaust capacity from the spray area. General de

sign concepts and operating considerations for the ventilation control of occupational exposures may be found in the most recent edition of Industrial Ventilation: A Manual of Recommended Practice , published by the American Conference of Governmen

tal Industrial Hygienists (ACGIH) [ACGIH 2004b]. The design and operation of a ventilated spray enclosure for MDI-based spray-on bed liners should include the following four parameters with the aim of containing and minimizing exposure to MDI and maintaining exposure to MDI monomer below the NIOSH 10-minute ceiling limit and OSHA 15-minute ceiling limit of 0.2 mg/m 3 : 1. The spray enclosure should be de

signed as a negative pressure enclo

sure to prevent leakage of airborne MDI into other work areas within the shop. Three different design configura

tions have been identified to lower MDI concentrations within the spray enclo

sure and prevent escape to adjacent work areas: ■ A spray booth similar to that used in the automotive paint spray in

dustry; or ■ A spray enclosure (smallest floor area and room volume compati

ble with the operation) that incor

porates local exhaust ventilation hood(s) to capture and remove MDI near the point(s) of genera

tion; or ■ A spray enclosure (smallest floor area and room volume compat

ible with the operation) that uses a general ventilation system to dilute airborne contaminants. The ventilation system’s make-up air supply and exhaust locations should be strategically placed to generate a directed air flow that pushes airborne contaminant to

ward the exhaust points to maxi

mize ventilation efficiency and contaminant control. 2. If MDI were removed solely by dilution ventilation using an efficient (well-mixed) system design , the recommended three30 MDI Exposure During Spray-on Truck Bed Liner and Related Applications enclosure (see Respiratory Protection in Recommendations). 

### Purge Time ■ To calculate the time required to exhaust an air volume equal to a single room air change, you must know the exhaust ca

pacity of the fan (as installed) as well as the dimensions of the spray area.

T= (L × W × H) Q where: T = time for one air change (minutes) L = length of spray enclosure (feet) W = width of spray enclosure (feet) H = height of spray enclosure (feet) Q = fan capacity in cubic feet per minute (cfm)
■ A minimum purge time of three air changes (3 × T) is recommended for spray enclosures that incorporate very good ventilation efficiency (that is, mix

ing factor close to 1.0), such as those discussed in item 1 above. Less efficient designs will need to multiply the calcu

lated time requirement by a mixing fac

tor between 2 and 10, depending upon the prevalence of dead air spots within the spray area [ACGIH 2004]. During the recommended purge time, workers en

tering the spray enclosure should con

tinue using respiratory protection. air changes would be sufficient to remove 95% of the airborne MDI af

ter spraying has ceased. However, NIOSH field experience has shown that gravitational settling contributes significantly to the removal of the MDI aerosol. When these two removal mechanisms act together, the time required to achieve three air changes was more than sufficient to reduce the MDI concentrations to less than 50% of the NIOSH ceiling limit in every field situation evaluated by NIOSH. During the purge time any worker entering the spray enclosure should continue to use the necessary respiratory protection (see Respiratory Protection section). 

### Ventilation System Capabilities ■ Obtain a site-specific exposure assess

ment that includes sampling data at de

sired intervals following the spraying op

eration. These data are the best way to determine the purge time (time required to reduce MDI concentrations consistent

ly below the NIOSH REL) required for your ventilation system. ■ In the absence of exposure assessment data, d etermine the time required for the ventilation system to exhaust an air vol

ume equal to a single air change. ■ Calculate the required purge time, allow

ing sufficient time for at least three com

plete air exchanges—or even longer for systems with poor air mixing. ■ During the purge time, use respirato

ry protection when entering the spray31 MDI Exposure During Spray-on Truck Bed Liner and Related Applications 

# APPENDIX C
This appendix contains additional informa

tion about full-facepiece, supplied-air respi

rators and a respiratory protection program.



### SUPPLIED-AIR RESPIRATORS Many issues pertaining to this industry led to the selection of the full-facepiece, sup

plied-air respirator as the most appropri

ate respirator during the spray-on process. These reasons include the following:
■ MDI is a potent sensitizer and a NIOSHapproved supplied-air respirator provides a higher level of protection, thus lowering the potential for sensitization. ■ A supplied-air respirator provides the high level of protection needed in a work environment in which concentations of MDI aerosol are highly variable with un

predictable spikes to concentrations well above the NIOSH REL. ■ A supplied-air respirator decreases the possibility of momentary breakthrough in a work environment in which an air-puri

fying filter cartridge would likely become clogged, leading to higher breathing re

sistance and leakage around the side of the mask. ■ Full-facepiece, supplied-air respirators provide the eye and dermal protection necessary from the aerosolized spray-on product. ■ An air-purifying respirator requires fre

quent cartridge changes due to the con

centrations documented.


### ELEMENTS OF A RESPIRATORY PROTECTION PROGRAM A complete respiratory protection program as required by 29 CFR 1910.134 (c) (1) (i) through 1910.134 (c) (1) (ix) shall include the following:
■ Procedures for selecting respirators for use in the workplace ■ Medical evaluations of employees re

quired to use respirators ■ Fit-testing procedures for tight-fitting res

pirators ■ Procedures for proper use of respirators in routine and reasonably foreseeable emergency situations ■ Procedures and schedules for cleaning, disinfecting, storing, inspecting, repair

ing, discarding, and otherwise maintain

ing respirators ■ Procedures to ensure adequate air qual

ity, quantity, and flow of breathing air for atmosphere-supplying respirators ■ Training of employees in the respiratory hazards to which they are potentially exposed during routine and emergency situations3 MDI Exposure During Spray-on Truck Bed Liner and Related Applications ■ Training of employees in the proper use of respirators, including putting on and removing them, any limitations on their use, and their maintenance ■ Procedures for regularly evaluating the effectiveness of the program Appropriate management is a critical part of an effective respiratory protection program. Therefore, the program should be evaluated regularly as required by 1910.134 (c) (1) and administered by a qualified program administrator as required by 1910.134 (c) (3). Workers using supplied-air respirators must follow the manufacturer’s instructions on how to maintain and verify the specified minimum air pressure for the respirator.33 MDI Exposure During Spray-on Truck Bed Liner and Related Applications 

# APPENDIX D Surveillance Guidelines for State Health Departments Work-Related Asthma
1 second (FEV 1 ) or peak expiratory flow rate. Airflow changes can occur spontaneously, with treatment, with a precipitating expo

sure, or with diagnostic maneuvers such as nonspecific inhalation challenge. Patterns of association can vary and include the following: ■ Symptoms of asthma that develop or worsen after a worker starts a new job or after new materials are introduced on a job (a substantial period can elapse be

tween initial exposure and development of symptoms) ■ Symptoms that develop within minutes of specific activities or exposures at work ■ Delayed symptoms that occur several hours after exposure (for example, dur

ing the evenings of workdays) ■ Symptoms that occur less frequently or not at all on days away from work and on vacations ■ Symptoms that occur more frequently when the affected worker returns to work ■ Symptoms that are temporally associat

ed with workplace exposure to an agent with irritant properties Work-related changes in medication require

ments can accompany these symptom pat

terns. 

### REPORTING GUIDELINES State health departments should encourage health-care professionals to report back all the diagnosed or suspected cases of asthma that are caused or exacerbated by workplace exposures or conditions. Reported cases should include asthma caused by sensitizers or irritants and should include cases of reac

tive airways dysfunction syndrome.



### SURVEILLANCE CASE DEFINITION The surveillance case definition requires 1. a health care professional’s diagnosis consistent with asthma and 2. an association between symptoms of asthma and work. Asthma is a chronic condition characterized by inflammation of the tracheobronchial tree associated with increased airways respon

siveness to a variety of stimuli. Symptoms of asthma include episodic wheezing, chest tightness, cough, and dyspnea, or recurrent attacks of bronchitis with cough and sputum production. The primary physiological mani

festation of airways hyperresponsiveness is variable or reversible airflow obstruction. It is commonly demonstrated by significant changes in the forced expiratory volume in3 MDI Exposure During Spray-on Truck Bed Liner and Related Applications 

# APPENDIX E
Contact Information for Selected States The following States have surveillance sys

tems for work-related asthma: 

### California California Department of Health Services Occupational Health Branch 850 Marina Bay Parkway Building P, 3 rd Floor Richmond, CA 94804–6404 510–620–5757 www.dhs.ca.gov/ohb/Default.ht m CAL/OSHA Consultation Service Department of Industrial Relations 2424 Arden Way, Suite 485 Sacramento, California 95825 916–263–5765 www.dir.ca.gov/DOSH/consultation.htm l 

### Connecticut State of Connecticut Department of Public Health 410 Capitol Avenue, Mail Stop: 11 OSP P.O. Box 340308 Hartford, CT 06134–0308 860–509–7744 www.dph.state.ct.us/BRS/EOHA/HPEEOH.htm l Connecticut Department of Labor Division of Occupational Safety and Health 38 Wolcott Hill Road Wethersfield, CT 06109 860–566–4550 www.ctdol.state.ct.us/osha/osha.htm 

### Massachusetts Massachusetts Department of Public Health Occupational Health Surveillance Program 250 Washington Street, 6 th Floor Boston, MA 02108 617 –624–5632 www.mass.gov/dph/bhsre/ohsp/ohsp.ht m MA Division of Occupational Safety On-site Consultation Program Department of Labor and Workforce Development 1001 Watertown Street West Newton, MA 02465 617–969–7177 w

ww.mass.gov/dos/consult/index.ht m 

### Michigan Michigan Department of Labor and Economic Growth Michigan Occupational Safety and Health Administration (MIOSHA) Consultation, Education, and Training Division 7150 Harris Drive P.O. Box 30659 Lansing, MI 48909–8149 517–322–1809 www.michigan.gov/cis/0,1607,7-154- 11407---,00.htm l35 MDI Exposure During Spray-on Truck Bed Liner and Related Applications Michigan State University Department of Medicine Occupational and Environmental Medicine 117 West Fee Hall East Lansing, MI 48824–1315 517–432–1008 www.oem.msu.ed u 

### New Jersey New Jersey Department of Health and Senior Services Occupational Health Surveillance Program P.O. 360, Room 701 Trenton, NJ 08625–0360 609–984–1863 www.nj.gov/health/eoh/survwe b NJ Department of Health and Senior Services Public Employees Occupational Safety and Health Consultation Project P.O. Box 360 Trenton, NJ 08625–0386 609–984–1863 www.state.nj.us/health/eoh/peoshweb/ peoshcon.ht m New Jersey Department of Labor and Workforce Development Division of Public Safety and Occupational Safety and Health P.O. Box 953, Trenton, NJ 08625 609–984–0785 www.state.nj.us/labor/lsse/lsonsite.htm l 

### New York State of New York Department of Health Center for Environmental Health Bureau of Occupational Health Flanigan Square 547 River Street, Room 230 Troy, New York 12180–2216 518–402–7900 www.health.state.ny.us/nysdoh/boh/ homeoccu.ht m New York State Department of Labor Division of Safety and Health Onsite Consultation Program State Office Campus, Bldg. 12, RM 168 Albany, New York 12240 518–457–2238 www.labor.state.ny.us / 

### Washington Washington State Department of Labor and Industries Safety and Health Assessment and Research for Prevention (SHARP) Program P.O. Box 44330 Olympia, WA 98504–4330 888–667–4277 www.lni.wa.gov/Safety/Research/default.as p