Solvent exposure and Parkinson’s disease

Shaun Wood worked was a painter and finisher  at Royal Air Force (RAF) bases across the world. During the early 1990s he was involved in the very intensive work preparing Tornado aircraft for the first Gulf War, in particular gluing anti-missile patches to the aircraft. This work was often done in confined spaces over long working hours.  He generally wore a respirator but these were not really adequate for the circumstances.

German Tornado Undergoing Maintenance

Shaun has been diagnosed with Multiple System Atrophy (MSA), which is a debilitating Parkinsonian syndrome that affects the nervous system. He is just 53 years of age.

Throughout his work Shaun was exposed to various solvents, but primarily trichloroethylene and dichloromethane. There is not a great deal of information about exposure to these solvents in aircraft maintenance. I have seen results from a survey carried out at an RAF base in Scotland where dichloromethane levels were measured during paint striping in the cockpit area of a Nimrod aircraft. There was only 1.5 m2 of paint removed, but the peak air concentrations were about 700 mg/m3. Results from three monitoring surveys where the British Health and Safety Executive sampled for dichloromethane during paint stripping on aircraft are shown in the following figure. The mean levels measured in each of these surveys were: 330, 790 and 1,960 mg/m3, and the highest individual level measured was 3,590 mg/m3.

Read full article on OH-world.org A blog about exposure science and occupational hygiene

http://johncherrie.blogspot.ie/2011/12/solvent-exposure-and-parkinsons-disease.html

*****

Below is a photo of one of the locations in the Irish Air Corps that used Dichloromethane, namely the NDT Shop of Engine Repair Flight. Yes that is a stream of the chemicals dripping out of the extractor fan and running down the wall. And yes that is dichloromethane, cresylic acid and the hexavalent sodium chromate all over the floor. The small barrel that is being dissolved by its contents contains Hydrofluoric Acid.

Some extracts from the Ambient Air Monitoring For Health and Safety at Work report dated 2nd August 1995

  1. Dichloromethane levels were measured in the engine shop in Wednesday the 12th and Thursday the 13th of July 1995 at the behest of Captain John Maloney who is still serving in the Irish Air Corps
  2. The level of dichloromethane found in ambient air in the engine
    cleaning area exceeded health and safety limits. 
  3. Levels of Dichloromethane were measured at 175.9ppm (622.5 mg/m3)  while the TWA health & safety limit for this chemical in 1995 was 50ppm.
  4. Significant levels of all parameters monitored were found in nearly all ambient air samples taken in the engine cleaning area.
  5. The ventilation in all areas monitored was deemed to be insufficient. It is thus recommended that mechanical heating and ventilation systems be adapted designed and installed in all areas monitored.

To summarise, the Irish Army Air Corps knew that Dichloromethane levels in the NDT shop in 1995 exceeded health & safety limits by 3.5 times yet officer management

  1. LEFT personnel of all ranks and none to rot in this exceptionally toxic working environment for a further 12 years.
  2. IGNORED the recommendation to design and install design a proper ventilation system, (they stuck in 2 x Xpelairs).
  3. NEVER re-tested the environment to see if the Xpelair fans worked, we suspect they made things worse by increasing evaporation rate.
  4. NEVER informed personnel of enlisted ranks that their workplace was contaminated to dangerous levels.

DELAY – DENY – DIE

Hexamethylene Diisocyanate – Just one of the toxic chemicals the Irish Air Corps and State Claims Agency want to hide from former personnel!

  1. Exposure can occur when isocyanates are curing or when cured isocyanates are heated.
  2. An individual’s response to isocyanate exposure can be immediate or may be DELAYED FOR SEVERAL YEARS.
  3. Skin exposure can also cause respiratory sensitisation.
  4. The odour threshold for isocyanates, i.e. the level at which an individual can smell an isocyanate, is typically higher than the allowed exposure limits.
  5. The Air Corps did eventually provide a “supplied air” respirator to spray paint & welding personnel. Unfortunately they sourced the “supplied air” from an old machine compressor located in ERF where the air had previously tested as 3.5 times over the allowed limit for Dichloromethane i.e. allowed limit was 50ppm and sourced air was from a location measured at 175ppm…out of the frying pan and into the fire.

Air Corps Hexamethylene Diisocyanate Usage

Hexamethylene Diisocyanates were a chemical component of polyurethane paint hardener used by the Spray Paint Shop (Dope Shop) at Baldonnel. For most of the existence of this shop personnel were NOT supplied with ANY PPE. The walls between the Spray Paint Shop and Engineering Wing Hangar & Workshops were not sealed and so Hexamethylene Diisocyanate and other chemicals entered these workplaces whilst spraying was in progress exposing all personnel.

Furthermore if a component could not be removed from an aircraft for spray painting it was spray painted in-situ in Engineering Wing Hangar whilst unprotected line & tech personnel worked in adjoining offices & workshops or on other aircraft in the hangar.

Visiting personnel to Engineering Wing hangar such as BFTS personnel doing an IRAN, Heli personnel doing an overhaul & even Military Police on a walkabout were also exposed.

A “waterfall” system with an extractor fan was also present. Personnel spray painted aircraft components toward the waterfall which captured most of the over-spray droplets. Fumes from this waterfall were then extracted by a fan, up a duct and released at approximately 3m height where the prevailing winds then carried the extracted fumes in the doors & windows of : 

  • 5th Maintenance Engineers
  • Air Corps Apprentice School
  • Avionics Squadron
  • BFW Stores
  • Engine Repair Flight
  • Old Tech Stores
  • Training Wing HQ Prefab
  • Parachute Shop

5-20% of people are prone to isocyanate sensitisation. and isocyanate cross sensitisation is a recognised phenomenon. Sensitisation is irreversible and unfortunately once sensitised it is next to impossible to avoid isocyanate allergy triggers in the modern environment as they are used to make all Polyurethane products.

It is also likely that health effects are suffered beyond the respiratory system & skin for example the gastric & nervous systems and it is also probable that sensitisation to isocyanates will lead to allergies to other unrelated chemicals leading to a cascade of triggering chemicals allergies & intolerance for over exposed individuals.

DELAY – DENY – DIE

Safe Handling of Cresols, Xylenols & Cresylic Acids

Introduction

Cresols, xylenols and cresylic acids are hazardous substances and dangerous both to people and the environment if handled improperly. Cresols, xylenols and cresylic acid products produced by Sasol Chemicals (USA) LLC are highly versatile materials and are used as intermediates in the manufacture of a wide variety of industrial products such as resins, flame retardants, antioxidants, and coatings. In these and other applications, cresylic acids can be stored, transferred, processed and disposed of safely when proper procedures and safeguards are used. 

“Cresol” refers to any of the three isomers of methylphenol (C7H8O) or combinations thereof. “Cresols” commonly refer to a mixture which is predominantly methylphenol but may also contain lesser amounts of other alkylphenols. “Xylenol” is a common name for any of the six isomers of dimethylphenol (C8H10O) or their various combinations. Material which is predominantly dimethylphenol but which also contains ethylphenols and other alkylphenols may be referred to as “Xylenols”. “Cresylic acid” is a generic term referring to various combinations of cresols, xylenols, phenol or other alkylphenols (ethylphenols, propylphenols, trimethylphenols, etc.). 

Purpose & Scope

The purpose of this document is to provide information gathered through Sasol’s long experience in the safe handling of cresylic acids. It focuses on basic and practical information about working safely with these substances. Additional references are provided and it is strongly recommended that these and others be consulted prior to working with cresylic acids. Please do not hesitate to contact your regional Sasol office if we can be of assistance in the safe storage, handling, processing and disposal of our products.

Hazards

Health Hazards

The primary dangers posed in handling cresylic acids are those resulting from physical exposure. Cresylic acids are highly corrosive and contact with exposed skin or mucous membranes causes severe burns. These burns progress from an initial whitening of the exposed skin to blackishbrown necroses within 24 hours after exposure. Cresylic acids also exhibit anesthetic properties. Therefore, victims frequently misjudge the extent of their exposure when the initial burning sensation rapidly subsides. This can result in prolonged contact, causing toxic effects in addition to the corrosive damage. 

Cresylic acids are readily absorbed through the skin and mucous membranes in liquid or vapor form and act as systemic toxins for which there is no established treatment. Relatively small areas of exposure (e.g. an arm or a hand) can allow sufficient absorption to cause severe poisoning. Progressive symptoms of such poisoning include headache, dizziness, ringing in the ears, nausea, vomiting, muscular twitching, mental confusion, loss of consciousness and, possibly, death from lethal paralysis of the central nervous system. Chronic exposure can lead to loss of appetite, vomiting, nervous disorders, headaches, dizziness, fainting and dermatitis. 

The Occupational Health & Safety Administration (OSHA) has established 5ppm or 22 mg/m3 permissible exposure limits (PEL’s) for cresols on an 8-hour time-weighted average basis. OSHA guidelines also indicate that adequate personal protective equipment (PPE) should be employed to avoid skin contact with cresols. Cresylic acids are not listed as carcinogens by OSHA, the International Agency for Research on Cancer (IARC) or the National Toxicology Program (NTP).

Environmental Hazards

Cresylic acids show high acute toxicity towards both fish and aquatic invertebrates and must be prevented from entering surface or ground waters. Depending upon the specific composition, the material may be classified as a marine pollutant. Please refer to the current label and safety datasheet.

Controls for Working with Cresols

Safe storage, handling, processing and disposal of cresylic acids begin long before they ever arrive on-site. Measures necessary to ensure the health and well-being of employees, customers, the community and the  environment include the development of effective administrative and engineering controls designed to specifically address the hazards associated with cresylic acids. Personal protective equipment (PPE) is integral to safe handling and should be viewed as the last line of defense against an accidental failure of the administrative and/or engineering controls. 

Administrative Controls

Administrative controls are the foundation of any program designed for safely handling cresylic acids. Every company is unique in how they run their business and establish administrative controls. Those specifically developed for working with cresylic acids should address comprehensive process planning, thorough communication of hazards to employees and extensive training of employees on the proper implementation of all safety measures.

Personal Protective Equipment (PPE)

All personnel who work with or near cresylic acids must use adequate personal protective equipment (PPE). The extent of the potential exposure and consideration of established permissible exposure limits (PEL’s) should dictate the level of protection necessary. Personnel working with or near lab-scale quantities should always wear safety glasses with side-shields or

chemical mono-goggles, chemical-resistant or impermeable gloves, long-sleeved shirts and trousers as a minimum.

Circumstances such as elevated temperature and pressure or vacuum conditions should dictate if more substantial protection is necessary, including face shields, chemically impermeable outerwear, and breathing protection. Personnel transferring larger quantities of cresylic acids, or working in areas where a line-break could result in similar exposure, should always wear full protective equipment.

Emergency Procedures

Physical Exposure – External

The primary dangers involved in working with cresylic acids are the corrosive and toxic effects resulting from a physical exposure. Studies suggest that the severity of the exposure depends more on the magnitude of the exposed skin area than the concentration of cresylic acid. Therefore, the critical factor in dealing with an external physical exposure to cresylic acids is to minimize the extent and duration of the contact. To this end, the immediate response must be thorough flushing of the exposed areas with copious amounts of running water to remove all the cresylic acid in contact with the skin or eyes. Any contaminated clothing should be removed as quickly and carefully as possible during this process to avoid any additional skin contact.

Any exposed areas will have readily absorbed the cresylic acids and may be evidenced by a characteristic whitening of the skin. After thorough flushing with water, a solution consisting of 2 parts polyethylene glycol 400 to 1 part ethanol (PEG/EtOH) should be liberally applied to any affected skin (avoid contact with eyes), allowed to remain 15 to 30 seconds and then flushed away with fresh running water. Continue the cycling of PEG/EtOH and water for at least 15 minutes and then finish with thorough washing with soap and water. This decontamination procedure reduces the severity of the exposure, but does not completely eliminate damage to the skin or toxic effects. Medical attention should be sought as soon as possible.

Spill Containment & Clean-Up

Spill containment and cleanup of cresylic acids should only be performed by properly trained personnel employing an appropriate level of protective equipment as dictated by the extent of the spill. Small to medium spills on land should be surrounded by and absorbed onto inert clay absorbent and transferred to a disposal container. Larger land-spills should be diverted away from waterways, contained with booms, dikes or trenches, and collected in a vacuum truck. Any residual cresylic acids remaining after vacuuming should be cleaned up using the clay absorbent. All soils affected by the spill should be removed and placed in approved disposal containers.

Water spills are of particular concern due to the acute toxicity of cresylic acids to marine life. Clean up efforts should focus on containing the spill and quickly removing the cresylic acids that settle in deeper areas of the waterway. This can be aided greatly if the flow of water can be slowed or stopped. Further efforts should focus on removing as much of the dissolved cresylic acids as possible from the water using activated charcoal.

The composition and extent of any spill should be evaluated against local guidelines (ex. SARA Title III and RCRA in the U.S.) and reported to the proper agencies, if necessary. Any non disposable clean-up equipment should be thoroughly decontaminated with soap and water after use.

Source : SASOL / USA

Safe Handling of Cresols, Xylenols & Cresylic Acids

 *****


Some significant points to note about Cresylic Acid

Below is a photo taken 10 years ago in the Irish Army Air Corps NDT shop,  part of the Avionics / ERF building complex. Ardrox 666 can be seen spilled on the ground where it was free to leach through a shore onto the grass verge outside. 

  • 25% of fresh Ardrox 666 used by the Air Corps was Cresylic Acid. This percentage was higher in waste Ardrox 666 as Dichloromethane evaporated.
  • That greenish / yellow stain dripping from the extractor fan is also Ardrox 666 from the air.

DELAY – DENY – DIE

What are Isocyanates?

What are Isocyanates?

An isocyanate is any chemical that contains at least one isocyanate group in its structure. An isocyanate group is a group of atoms containing one nitrogen atom attached by a double covalent bond to one carbon atom, which in turn is attached by a second double bond to an oxygen atom (indicated in structure as -N=C=O). (Do not confuse this with the cyanate functional group which is arranged as –O–C≡N). A chemical containing two such isocyanate groups is called a diisocyanate. Common examples are toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and methylene diphenylmethane diisocyanate (MDI).

Isocyanates (a description which includes diisocyanates) are the raw materials that make up all polyurethane products. Isocyanates react with compounds containing alcohols to produce polyurethane polymers – which are used in polyurethane foams, thermoplastic elastomers and “2 pack” type polyurethane paints to improve the performance, durability and finish of painted surfaces. Jobs that may involve exposure to isocyanates include painting with polyurethane products, foam-blowing and the manufacture of polyurethane products like insulation materials, surface coatings, furniture, foam mattresses, under-carpet padding, packaging materials, laminated fabrics, polyurethane rubber, adhesives and also exposure can occur during the thermal degradation of polyurethane products.

Health Effects

Exposure to hazardous materials may be acute or chronic. Acute exposures refer to single high concentration exposures over shorter periods, while chronic exposures are repeated or continuous exposures over longer periods. Exposures to any toxic material may have either acute, immediate effects and/or chronic, long term health effects.

Inhalation:

Isocyanates are known to have a strong effect on the respiratory tract in some people. It is reported that there is a susceptible group in the population (estimated to be 5-20% of workers who are exposed occupationally) who can become sensitised to Isocyanates. Sensitization is the body’s hyper-reactive (allergy-like) response to a substance which has been touched or inhaled by a susceptible individual. Sensitization may develop as a result of a large single overexposure, for example, from a spill or accident, or from repeated overexposure at lower levels.

Once sensitised, these people, when later exposed to even very low concentrations of isocyanates even at levels below the exposure standard, can react by developing asthma-like symptoms, such as chest tightness, cough, wheezing and shortness of breath. Such attacks may occur up to several hours after cessation of exposure (for example, during the night after exposure) but, if a person is particularly sensitive, the attack can occur earlier or immediately. This sensitisation is essentially irreversible and can prevent any further work for the individual in their job using Isocyanates or any position associated with use of Isocyanates – even at very low levels below the regulated exposure level and that may not affect others. Many spray painters working in smash repair shops have had to leave the industry because they are sensitised to isocyanates.

An individual’s response to isocyanate exposure can be immediate or may be delayed for several years. Asthmatic people are more prone to sensitisation and other adverse reactions. Persons with a history of asthma, allergies, hay fever, recurrent acute bronchitis or any occupational chest disease or impaired lung function is advised against risking exposure to isocyanates. In rare cases, death has occurred from a severe asthma attack after significant isocyanate exposure.

Skin

Isocyanates are also skin irritants (causing inflammation and dermatitis) and there is some evidence that skin exposure can also cause respiratory sensitisation.

Eyes

Isocyanates are an irritant to the eyes. Splashes can cause severe chemical conjunctivitis.

Other Health Effects

Other health effects which have been reported include liver and kidney dysfunction. Some Isocyanate materials are considered to be potential human carcinogens (IARC).

Spraying Isocyanate Paints

Spray painters need to understand the health risks involved in spraying polyurethane paints – these are the two-pack mixes of polyurethane paints and possibly also in the one-pack moisture-cured mixes. These products are widely used in the automotive and other industries because of their excellent gloss, hardness, adhesion and chemical resistance.

The major hazard with spraying polyurethane paints is breathing the mist or aerosol droplets of the paint spray and absorbing the isocyanate and other components into your lungs.

The odour threshold for isocyanates, i.e. the level at which an individual can smell an isocyanate, is typically higher than the allowed exposure limits. In other words, if a painter smells the sweet, fruity, pungent odour of an isocyanate, they are probably already overexposed. That is why the recommended respiratory protection for employees spraying isocyanates is a supplied air respirator and not an air purifying respirator (i.e. filter cartridge style). The issue with use of air purifying respirators is that they will reach a point at which the filter becomes saturated and will no longer capture the isocyanate or other solvents. When that filter breakthrough happens, an Isocyanates overexposure can occur, potentially causing an irreversible sensitization. Use of a supplied air system removes this filter change factor – it does not rely on the painter changing his gas/vapour filters at appropriate intervals.

Note: if isocyanate-containing paint is applied by brush, roller or dipping, in a well ventilated area, there is generally no more hazard than with ordinary paints. These application methods usually do not produce the higher concentrations of isocyanate vapour associated with spraying.

After curing, polyurethane paints contain no free isocyanates and are not hazardous under normal use. However, welding or burning of polyurethane coated surfaces can release a range of contaminants. Gases or vapours evolved can include HDI, TDI, MDI as well as many other compounds (metal fumes, organic gases or vapours, particulates), depending on the original polyisocyanate resin used. When welding or cutting metal coated with a polyurethane coating, a worker may be exposed to a range of these decomposition products which will vary depending on type of process being used to weld or cut, the nature of the base metal and type of coating. Respiratory protection that is suitable for welding applications will also provide suitable respiratory protection in these cases

Source 3M Australia / New Zealand

http://multimedia.3m.com/mws/media/777847O/isocyanates-3m-techupdate.pdf

 *****

Some significant points to note from this 3M document.

  1. Exposure can occur when cured isocyanates are heated.
  2. An individual’s response to isocyanate exposure can be immediate or may be DELAYED FOR SEVERAL YEARS.
  3. Skin exposure can also cause respiratory sensitisation.
  4. The odour threshold for isocyanates, i.e. the level at which an individual can smell an isocyanate, is typically higher than the allowed exposure limits.
  5. The Air Corps did eventually provide a “supplied air” respirator to spray paint & welding personnel. Unfortunately they sourced the “supplied air” from an old machine compressor located in ERF where the air had previously tested as 3.5 times over the allowed limit for Dichloromethane i.e. allowed limit was 50ppm and sourced air was from a location measured at 175ppm…out of the frying pan and into the fire.

Air Corps Isocyanate Usage

Isocyanates were used by the Spray Paint Shop (Dope Shop) at Baldonnel. For most of the existence of this shop personnel were NOT supplied with ANY PPE. The walls between the Spray Paint Shop and Engineering Wing Hangar & Workshops were not sealed and so isocyanates and other chemicals entered these workplaces whilst spraying was in progress exposing all personnel.

Furthermore if a component could not be removed from an aircraft for spray painting it was spray painted in-situ in Engineering Wing Hangar whilst unprotected line & tech personnel worked in adjoining offices & workshops or on other aircraft in the hangar.

A “waterfall” system with an extractor fan was also present. Personnel spray painted aircraft components toward the waterfall which captured most of the over-spray droplets. Fumes from this waterfall were then extracted by a fan, up a duct and released at approximately 3m height where the prevailing winds then carried the extracted fumes in the doors & windows of Avionics Squadron & Engine Repair Flight exposing further unprotected personnel.

Sensitisation is irreversible and once sensitised it is next to impossible to avoid isocyanates in the modern environment. It is also likely that health effects are suffered beyond the respiratory system & skin for example the gastric & nervous systems. 

DELAY – DENY – DIE