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June 11, 2010
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*While Chemwatch has taken all efforts to ensure the accuracy of information in this publication, it is not intended to be comprehensive or to render advice. Websites rendered are subject to change.
People often add chemical and/or enzymatic drain cleaners to their plumbing systems to remove obstructions or to prevent or slow their formation. Such blockages are usually the result of an accumulation of soap, grease, paper products, hair, human waste, and other foreign materials. These materials are normally deposited in drains, pipes, and sewer lines. But the design of piping systems, the quantity of material introduced, and flow problems allow the occurrence of blockages.
Chemical and enzymatic drain cleaners have the appeal of being potentially easy to use, quick in their degradation of the blockage, and often are less expensive than mechanical drain cleaning equipment. Chemical cleaners work via their reactive chemical nature; enzymatic cleaners work via slower biological/digestive type reactions. Because of their chemical reactivity, coupled with the often unknown contents and configurations of plumbing systems, improper application of chemical drain cleaners can result in unexpected chemical reactions, splashes, and other effects which may result in personal injury and/or property damage. 
Drain Cleaner Categories:
There are four primary categories of drain cleaners:
Caustics: lye, sodium hydroxide, caustic soda
Oxidizers: sodium hypochlorite
Acids: sulfuric acid, hydrochloric acid
Enzymatic: biochemical waste digesters
Potential Problem Areas:
Product packaging and labeling
Failures of piping and/or fixtures
Chemical reactions that produce heat, gas eruptions, or toxic gases 
Drain Cleaner Implications:
You can remove obstructions or restrictions by using mechanical or chemical removal methods. Chemical removal employs generation of heat and reaction between the drain cleaner and the blocked material. Such chemical reactions have potential to be very strong and expel toxic gases. Additionally, chemicals can cause burns, react with things other than those in the blockage, and produce other undesirable physical effects. Chemical drain cleaners can damage plumbing and surrounding surfaces. Since they are generally denser than water, they sink to a lowest possible point. Enzymatic drain cleaners are less likely to acutely harm the human body by direct contact with the skin and/or eyes than chemical drain cleaners. By reformulating and introducing slower reacting methods, scientists have reduced the potential for some hazards. But these safer cleaners tend to be less effective at dissolving the obstruction or blockage. 
Drain Cleaner Issues
Heat caused by chemical drain cleaners may soften plastic (PVC) pipes. The heat, combined with the chemical reaction, may damage corroded old pipes. Acid drain cleaners corrode stainless steel, damage aluminium fixtures, and can crack porcelain. And if a chemical drain cleaner does not remove the blockage, the chemical may remain stay in the piping system in an unreacted state.
Sometimes, people try to clear a blockage by using more than one product. If you add an acid drain cleaner into pipes that already contain caustic drain cleaners, it can cause a strong acid-base neutralization reaction. This type of reaction usually results in the formation of a salt and water. But in the worst case scenario, it can generate extreme heat, and the liquids may spatter or erupt from the drain. Diluting concentrated caustics and acids can also generate heat. Depending on the initial and final solution concentrations, this “heat of solution” can be considerable and variable. If the chemical remains unreacted in the piping system, anyone who tries to clear the blockage by mechanical means (e.g. by using a plunger) may unknowingly have the potential of exposure to the chemical.
If you add water to a concentrated caustic or acid, it may cause boiling and spattering of the resulting solution. However, if the caustic or acid is slowly and carefully added to water, you can minimize the chances of boiling and spattering. Standards often recommend using the term “concentrated” for aqueous solutions as a warning for potential injuries to tissue or negative health effects. Be advised that chemical texts often use the same term for nearly pure solutions.
Due to differences in volume between liquids and gases, reactions which generate gases may result in possible eruptions and pressure buildup. Combining caustic acid drain cleaners containing sodium hypochlorite with other household chemicals can form toxic gases such as chloramine or chlorine. The oxidation of organic materials can cause the formation of gases such as carbon dioxide, hydrogen, and/or organic gases. Carbonates in acid drain cleaners and concrete can react to liberate carbon dioxide gas.
When you use an enzymatic treatment, it typically requires at least one overnight application. And you cannot use the drain during this time. Most treatments require additional applications in order to establish a colony. And since bacteria are regularly washed out as the drain is used, such treatments recommend monthly maintenance applications, resulting in increased cost, maintenance, and inconvenience. Adding cleaning solutions that include bleach, disinfectants, solvents, or other chemicals can be harmful to the established bacterial colony. 
Drain Cleaner Summary
Chemical and enzymatic drain cleaners are potentially dangerous to use. They can react with human tissue in a similar manner as to the organic materials in drain blockages. Hazardous and toxic gases can be generated, as well as spattering and/or eruptions. Standards exist addressing these potential hazards with recommendations for: proper and safe use, packaging and labeling, and personal protection. Recommendations have been made to use preventive methods such as:
avoiding pouring grease down drains
using strainers to trap food, hair, and other articles
regular biological/enzymatic treatments
pouring hot water down the drain weekly to keep the drain free flowing. The water should be poured directly into the drain rather than in the basin, so as to avoid cracking of porcelain fixtures.
If a drain requires cleaning, consumer advocates recommend the use of mechanical devices, followed by removal and cleaning of traps and cleanout plugs. Chemical cleaners are recommended only as a last resort; if the chemical drain cleaner fails to work, a professional should be contacted and the situation should be explained. 
Chemical Drain Cleaner Precautions
A chemical drain cleaner, if used without caution, can be hazardous to the operator. Handling a chemical drain cleaner with safety in mind will guarantee you can complete your task without getting hurt.
When using the drain cleaner make sure you never come in physical contact with the chemicals. It is highly suggested the user wear a pair of rubber gloves and protective goggles in case any chemicals splash out of the drain. After the operation, be sure to avoid the drain area as chemicals are likely to bubble up, which releases harmful fumes and liquids.
You should never use a chemical drain cleaner on a garbage disposal. The chemicals can linger in the garbage disposal after the work was done on the drain. If someone decided to turn on the disposal, chemicals could slash and cause bodily harm.
While operating with chemical drain cleaners, be sure to avoid using a plunger. Plungers have the potential to pull up the used chemicals which could spill on the operator. This applies both during and after using chemical drain cleaner.
It is very important not to mix different types of drain cleaner. Mixing chemicals can be a dangerous concoction especially if you mix an alkali cleaner and an acid cleaner together. The mixture has the potential to be explosive.
Do not use chemical drain cleaner on a completely clogged drain. The chemicals will remain on top of the clog and further increase the difficulty of removing the clog. 
PermaFlow Drains (2009) Drain Cleaners http://www.permaflow-drain.com/drain-cleaner.html on 1-6-2010
Goodway (2010) Drain Cleaner and Drain Cleaning from http://www.goodway.com/drain-cleaner.htm on 1-6-2010
Revised poisons and medicines scheduling arrangements to be implemented on 1 July 2010
Poisons and medicines scheduling is a national classification system that controls how chemicals and medicines are made available to the public. Generally, the scheduling of agricultural chemicals and veterinary medicines occurs through the APVMA’s registration and reconsideration processes and is undertaken by a committee within the Department of Health and Ageing (DoHA). Under a revised legislative framework for the scheduling of chemicals, new decision making powers will be implemented from 1 July 2010. Revised administrative arrangements include changes to the structure of the scheduling committee and new streamlined decision making processes. The changes apply to:
all outstanding applications with the APVMA as of 1 July 2010
new scheduling applications received via the APVMA after 1 July 2010
Future changes affecting renaming of the Poisons Standard and cost recovery arrangements are also planned. Detailed information concerning the revised scheduling arrangements and general information about the scheduling of medicines and poisons can be found on the Therapeutic Goods Administration website.
APVMA, 14 May 2010 http://www.apvma.gov.au
Safe Work Australia reports a decrease in some occupational diseases
Mr Tom Phillips, Safe Work Australia Chair, recently announced the release of Occupational Disease Indicators. This publication supports the priority of the National OHS Strategy 2002-12, to more effectively prevent occupational disease. The data for the indicators published in the report are sourced primarily from workers’ compensation claims data from the National Data Set for Compensation Based Statistics. Additional data sources are used to collect information on diseases that are highly attributed to exposure to hazards in the workplace. This report is the third in a series of biennial reports, with the main purpose of highlighting changes in the incidence rates of occupational diseases. Most occupational diseases are multi-factorial with workplace hazard exposures as one contributing factor to the cause of the disease. The major findings from the new report include:
From 2000-01 to 2006-07 decreasing trends were observed for musculoskeletal disorders, mental disorders, infectious and parasitic diseases, contact dermatitis and cardiovascular diseases.
For the same period, no clear display of an overall trend of increase or decrease was observed for noise-induced hearing loss, respiratory diseases or occupational cancers.
According to Mr Phillips, it is important to monitor and observe these changing trends. “There is often under-reporting of occupational diseases through workers’ compensation as many diseases have long latency periods, while for other diseases, the link between cause and effect can be difficult to establish. “Safe Work Australia is continuing to undertake research on the types of hazards currently found in the workplace that may cause occupational disease and the measures taken to reduce the impact on workers.” Mr Phillips said. The full report can be found at: http://www.safeworkaustralia.gov.au/swa/AboutUs/Publications/OccupationalDiseaseIndicators.htm
SafeWork Australia, 12 May 2010 http://www.safeworkaustralia.gov.au
FSANZ approves novel food sterol changes
Food Standards Australia and New Zealand (FSANZ) have backed a generic definition for phytosterols, phytostanols and their esters to replace the formulation-specific approvals that exist at the moment. In approving draft regulations on the matter, FSANZ established two main criteria for a generic classification that won the support of major players in the area such as Unilever, Kraft and Raisio, which lodged the application for the generic novel foods status in March, 2009. These were that safety and efficacy could only be proven if the plant sterol in question contained 95 per cent desmethyl sterols - the common forms of plant sterols contained in, “current commercial and well-studied preparations.” The other related to placing limits on the use of solvents. FSANZ determined these two elements were required in addition to criteria drawn from a 2008 monograph produced by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Currently, specific types of plant sterols taken from vegetable or tall oil sources may be added to four approved food categories: low-fat milk, certain types of breakfast cereals, edible oil spreads and low-fat yoghurt. “The weight of evidence supports the safety of plant sterols at present levels of consumption irrespective of the combination or proportion used of the individual phytosterol or phytostanol components used or their source,” FSANZ said. “FSANZ concludes that phytosterols, phytostanols and their esters are bioequivalent in terms of their food safety properties.” Others to support the amendments included the Food Technology Association of Australia; Arboris; the Australian Food and Grocery Council; Cognis Australia; Forbes Medi-Tech; the Dietitians Association of Australia and the National Heart Foundation of Australia. However Raisio had reservations. It suggested the solvent limit should be 1000ppm not 50ppm, as this was unachievable for many suppliers. But Cognis said the opposite recommending 50ppm. Furthermore, Raisio stated there should be no requirement for a fresh application for reduced fat cheese to be included as one of the approved food matrixes.
Nutra Ingredients, 10 May 2010 http://www.nutraingredients.com
Public hearings on methyl bromide reassessment
New Zealand’s Environmental Risk Management Authority (ERMA) is conducting a series of public hearings on the reassessment of fumigant methyl bromide. The hearings are an opportunity for submitters to present their views on the future use of methyl bromide to the decision-making committee of the Environmental Risk Management Authority. ERMA has released an Update Paper for the Authority ahead of the hearings. This includes a summary of submissions and any further relevant new information as well as the staff’s final recommendations in light of submissions. Members of the public are welcome to attend the hearings, but only submitters may present their views. A copy of the Update Paper can be found at: http://www.ermanz.govt.nz/resources/publications/pdfs/Methyl_bromide_update_paper_Final.pdf
ERMA, 3 May 2010 http://www.ermanz.govt.nz