Number Of Chemical Products Research Articles

Chemical Use and Associated Health Concerns in the Semiconductor Manufacturing Industry

BackgroundResearch on the status of many chemicals used in the semiconductor industry is needed. The purpose of this study was to describe the overall status of chemical use in the semiconductor industry in Korea and to examine it from a health perspective.MethodsData on the status of chemical use and safety data sheets at 11 of 12 major semiconductor workplaces in Korea were collected. The number of chemical products and chemical constituents, quantities of chemicals, and trade secret ingredients used, as well as the health hazards were examined.ResultsOn average, 210 chemical products and 135 chemical constituents were used at the surveyed workplaces. Among all chemical products, 33% (range: 16–56%) contained at least one trade secret ingredient. Most of the trade secret ingredients were used in the photolithography process. Several carcinogens, including sulfuric acid, chromic acid, ethylene oxide, crystalline silica, potassium dichromate, and formaldehyde were also used. Only 29% (39 of 135) of the chemical constituents had occupational exposure limits, and more than 60% had no National Fire Protection Association health, safety, and reactivity ratings. Based on the aforementioned results, this study revealed the following. First, many chemical products and constituents are being used in the semiconductor industry and many products contained trade secret ingredients. Second, many products contained significant amounts of carcinogenic, mutagenic, and reproductive toxicant materials.ConclusionWe conclude that protecting workers in the semiconductor industry against harm from chemical substances will be difficult, due to widespread use of trade secret ingredients and a lack of hazard information. The findings of the status of chemical use and the health and safety risks in semiconductor industry will contribute to epidemiological studies, safe workplace, and worker health protection.

Chemical use in the semiconductor manufacturing industry.

The semiconductor industry is known to use a number of chemicals, but little is known about the exact chemicals used due to the ingredients being kept as a trade secret. The objective of this study was to analyze chemical use using a safety data sheet (SDS) and chemical inventory provided by a major semiconductor company, which operated two factories (A and B). Descriptive statistics were obtained on the number of chemical products and ingredients, photoresists, and carcinogens, classified by the International Agency for Research on Cancer (IARC), as well as trade secret ingredients. The total chemical use per year was estimated from chemical inventories mass (kg). A total of 428 and 432 chemical products were used in factories A and B, respectively. The number of pure chemical ingredients, after removing both trade secret ingredients and multiple counting, was 189 and 157 in factories A and B, respectively. The number of products containing carcinogens, such as sulfuric acid, catechol, and naphthalene was 47/428 (A) and 28/432 (B). Chemicals used in photolithography were 21% (A) and 26% (B) of all chemical products, and more than 97% among them were chemicals containing trade secret ingredients. Each year, 4.3 and 8.3 tons of chemicals were used per person in factories A and B, respectively. Because of the high level of commercial secrecy and the use of many unregulated chemicals, more sustainable policies and methods should be implemented to address health and safety issues in the semiconductor industry.

Procedure for Evaluating Stabilization of Road Materials with Nontraditional Stabilizers

In response to the need to find cost-effective stabilizers, a large number of chemical products are being marketed as potential solutions. Traditional laboratory tests have not been able to predict the performance of these materials satisfactorily. A solution is for suppliers to construct experimental sections several hundred meters long. However, that becomes an expensive exercise, since each type of soil in a region would have to be used. An evaluation technique has been developed that allows test panels to be constructed in the field at low cost with a range of soils and stabilizers and that takes into account local environmental conditions and traffic. The aim of this paper is to present this evaluation technique and the results with a range of stabilizers and soils. The paper describes construction of the 1- × 3-m test panels and the subsequent testing protocol. Several materials, ranging from sandy to clayey, were tested with different generic stabilizers, such as polymers, enzymes, and ionic soil stabilizers. Control panels without additives were also constructed. The testing regime conducted over 8 months included regularly measuring the following: the in situ California bearing ratio with a dynamic cone penetrometer, both at the in situ moisture content and after soaking for 2 h; density and moisture; and permeability. Visual observations about performance were also noted. The test panel procedure is a cost-effective solution for evaluating the potential strength gain of stabilizers with a range of soils. As is known, stabilizers must be tailored to soil properties, because stabilizers do not all have the same effect.

Methanogenic Toxicity and Anaerobic Biodegradation of Chemical Products in Use in a Brewery

Brewery industry effluents, as any other industrial effluent, contain a number of chemical products that could be toxic in biological wastewater treatment plants. Most of these products come from clean in place (CIP) systems, i.e. detergents and disinfectant, and from lubrication systems. To evaluate the toxicity effect of these compounds on an anaerobic effluent treatment pilot plant, studies of methanogenic activity were carried out. The results showed that the synthetic lubricant evaluated had a high toxicity level, compared to the organic lubricant; the disinfectant showed inhibition to some extent. To decrease the toxicity effect, the recovery and reutilization of these chemicals are suggested. Experiments to study the feasibility of adapting anaerobic sludge to these compounds were carried out. Working with UASB reactors, the adaptation of the sludge takes place in the presence of the most toxic chemical products; certain inhibition was observed on methanogenic bacteria in the reactor where a disinfectant was added, even though there was sludge wash out. In general a decrease in the operational behaviour was observed after adding the compound, a new steady state was reached in absence of the toxic compounds, in terms of alkalinity ratio, removal of COD, methane production. The reactors were able to be recovered and to be adapted again.

Methanogenic toxicity and anaerobic biodegradation of chemical products in use in a brewery

Brewery industry effluents, as any other industrial effluent, contain a number of chemical products that could be toxic in biological wastewater treatment plants. Most of these products come from clean in place (CIP) systems, i.e. detergents and disinfectant, and from lubrication systems. To evaluate the toxicity effect of these compounds on an anaerobic effluent treatment pilot plant, studies of methanogenic activity were carried out. The results showed that the synthetic lubricant evaluated had a high toxicity level, compared to the organic lubricant; the disinfectant showed inhibition to some extent. To decrease the toxicity effect, the recovery and reutilization of these chemicals are suggested. Experiments to study the feasibility of adapting anaerobic sludge to these compounds were carried out. Working with UASB reactors, the adaptation of the sludge takes place in the presence of the most toxic chemical products; certain inhibition was observed on methanogenic bacteria in the reactor where a disinfectant was added, even though there was sludge wash out. In general a decrease in the operational behaviour was observed after adding the compound, a new steady state was reached in absence of the toxic compounds, in terms of alkalinity ratio, removal of COD, methane production. The reactors were able to be recovered and to be adapted again.

Tighter rules urged for chemical rail shipments

The National Transportation Safety Board (NTSE) last week approved a staff report calling for an increase in the number of chemical products that must be shipped in pressurized rail tankcars, and demanding better training for rail workers and emergency personnel who deal with train accidents involving hazardous chemicals. The report is part of a major safety study on railroad accidents begun in 1988. In looking at rail accidents involving chemicals, NTSB members were disturbed by several problems. One is that many chemicals, although labeled hazardous, still are transported in tankcars that don't have optimum safety devices, such as shields to protect their ends from puncture, or thermal shielding for fire protection. There is no comprehensive regulation as to which chemicals must be carried in the more protected cars. NTSB staff report that perhaps as much as 10 to 15% of materials in nonpressurized tankcars are hazardous chemicals. In 1989, 1.52 million carloads of hazardous material ...