# Noise Sources and Control, and Exposure Groups in Chemical Manufacturing Plants
## 4 Discussion
### Noise Control for Chemical Manufacturing Plants
#### 4.3.1 Workplace Regulation  
The health impacts resulting from workplace exposures have resulted in health and safety regulation. Workplace health and safety regulations when fully implemented, result in the reduction of illnesses whilst also giving income security to employees [116]. Although workplace health and safety regulations have not fully eliminated workplace hazards, the implementation of these regulations has reduced workplace injuries and occupational illnesses. The noted reduction in workplace injuries and occupational illnesses is evidence of positive enforcement and inspection outcomes conducted by the regulator through inspectors or compliance safety and health officers [117; 118; 119]. Noise regulation compliance means assigning a limit to the hazard level and the imposition of punitive measures in case of non-compliance [118]. The NIHL regulations in SA and the control of noise at work regulations in the UK are examples of noise-specific workplace health and safety regulations. The impact of noise regulation on reducing NIHL cases can however only be measured in the presence of data comparing changes in illness rates for inspected and non-inspected workplaces [120]. Regulatory Control of Plant Equipment  
The legal requirement for the specification of noise emission data of tools, equipment and machinery used in industry is an important regulatory tool in noise reduction efforts for both new and existing plants [121]. Buying quieter plant equipment shifts the focus to equipment designers and manufacturer to meet regulatory noise emission specifications. The buy quiet programme is a NIOSH noise prevention initiative which is composed of (a) a list of existing plant machinery and equipment along with the listed noise levels; (b) company policy statement committing to buying quiet; (c) materials and tools for educating and promoting the buy quiet programme; and (d) cost-benefit analysis for buying quiet. In the buy quiet programme, manufacturers are encouraged to design quieter equipment and machinery whilst companies are also encouraged to buy or rent equipment which is quieter [122]. Noise emission data specification related legislation has however been largely ignored and both equipment designers and purchasers are said to only pay lip service to the requirement [18]. The noise ranges extrapolated on Table 2 attest to this fact. Additional requirements that can be built into the noise data sheets requirements for machinery include placing additional restrictions on machinery containing tonal and impulsive noise components. Plant owners have to consider the cost effectiveness of selecting machinery with low noise emission levels during the design phase of a plant or selection of new machinery [109]. Due to the interconnectedness of machinery in chemical manufacturing plants, noise prediction incorporating all noise emitting machinery should be done during the design phase of new installations [80; 84; 85; 109]. Regulatory Control through Inspection and Enforcement of Noise Regulations  
Noise regulations are intended for worker protection in the workplace and are implemented by the employer whilst the regulator conducts inspection and enforcement [123]. The inspection and enforcement are conducted to ensure legal compliance to health standards [124]. The inspectors use preventative tools such as risk evaluation, promotion of best practices, information and awareness campaigns, guidance and sanctions during inspections to secure compliance to health and safety regulation [125]. Between October 2015 and September 2016, OSHA issued 691 citations for 370 inspections conducted with penalties amounting to $1,665,895 for the violation of the noise standard. The chemical manufacturing sector received 20 citations in 10 inspections with penalties amounting to $105,897 whilst the plastics and rubber producers were issued with 35 citations for 18 inspections with penalties amounting to $157,303. [126].