ObjectiveTo analyze the causes of occupational acute 1,2-dichloroethane (1,2-DCE) poisoning accident during the use of polyurethane grouting materials for waterproof plugging operation in the construction industry. Methods By combining the clinical symptoms of the patient, worksite survey of occupational health and workplace occupational hazards monitoring method, the cause of an occupational acute 1,2-DCE poisoning accident was investigated at a construction site during the use of polyurethane grouting material for waterproofing and plugging operations. Results The patient was engaged in waterproof grouting work using polyurethane grouting material. The main volatile organic components in the raw materials were 1,2-DCE, with traces of dichloromethane, methyl acetate and others. The result of post-incident on-site investigation showed that the short-term exposure concentration of 1,2-DCE in the workplace air was 578.70 mg/m³, which was more than 30 times higher than the national occupational health standard limit. The mass concentration of 1,2-DCE in the patient's blood was 230 μg/L. Combined with the patient's occupational hazard exposure history, clinical manifestations, worksite survey of occupational health, and laboratory test results, according to GBZ 39-2016 Diagnosis of Occupational Acute 1,2-Dichloroethane Poisoning, this incident was diagnosed as a severe occupational acute 1,2-DCE poisoning event caused by the use of inferior polyurethane grouting material. Conclusion The excessive concentration of 1,2-DCE in the workplace air is the main cause of this poisoning accident. Construction sites with confined space operations should improve various occupational health management systems, occupational health engineering protective facilities, and personal protective equipment must be provided for workers.

Objective To investigate the association between the gene polymorphisms of the DNA damage repair gene X-ray repair cross-complementing gene 1 (XRCC1) and susceptibility to chromosome damage in workers exposed to low-concentration benzene in the jewelcrafting industry.Methods A total of 286 workers exposed to benzene in jewelcrafting enterprises were enrolled as study subjects from January 2013 to December 2014.Gas chromatography was used to measure benzene concentration in workplace,cytokinesisblock micronucleus test was used to analyze the level of chromosome damage in peripheral blood,and the Sequenom technique was used to determine the single nucleotide polymorphisms of XRCC1.Results The timeweighted average concentration of benzene in workplace was ＜0.6 ～1.8 mg/m3,lower than the national occupational exposure limit (6 mg/m3).The distribution of allele frequencies met the Hardy-Weinberg equilibrium in genetics(P＞0.05).Increase in age(RR=1.38,95％CI 1.06～3.75) and increase in working years (RR=1.45,95％CI 1.18～2.58) were risk factors for the increase in micronucleus frequency.Compared with those with the wild-type homozygous genotype,the individuals with XRCC1 rs25487 CT genotype showed a significantly higher risk of increase in micronucleus frequency (RR=1.51,95％CI 1.28～3.87,P＜0.05),and the individuals with XRCC1 rs1799782 AA genotype also showed a significantly higher risk of increase in micronucleus frequency (RR =1.65,95％ CI 1.30～3.12,P＜0.05).There was no clear association between XRCC1 rs25489 polymorphisms and micronucleus frequency (P＞0.05).Conclusion Exposure to lowconcentration benzene may cause chromosome damage in workers exposed to benzene,and the XRCC1 polymorphisms rs 25487 and rs 1799782 may be associated with chromosome damage induced by benzene.

Objective To investigate the association between the gene polymorphisms of the DNA damage repair gene X-ray repair cross-complementing gene 1 (XRCC1) and susceptibility to chromosome damage in workers exposed to low-concentration benzene in the jewelcrafting industry.Methods A total of 286 workers exposed to benzene in jewelcrafting enterprises were enrolled as study subjects from January 2013 to December 2014.Gas chromatography was used to measure benzene concentration in workplace,cytokinesisblock micronucleus test was used to analyze the level of chromosome damage in peripheral blood,and the Sequenom technique was used to determine the single nucleotide polymorphisms of XRCC1.Results The timeweighted average concentration of benzene in workplace was ＜0.6 ～1.8 mg/m3,lower than the national occupational exposure limit (6 mg/m3).The distribution of allele frequencies met the Hardy-Weinberg equilibrium in genetics(P＞0.05).Increase in age(RR=1.38,95％CI 1.06～3.75) and increase in working years (RR=1.45,95％CI 1.18～2.58) were risk factors for the increase in micronucleus frequency.Compared with those with the wild-type homozygous genotype,the individuals with XRCC1 rs25487 CT genotype showed a significantly higher risk of increase in micronucleus frequency (RR=1.51,95％CI 1.28～3.87,P＜0.05),and the individuals with XRCC1 rs1799782 AA genotype also showed a significantly higher risk of increase in micronucleus frequency (RR =1.65,95％ CI 1.30～3.12,P＜0.05).There was no clear association between XRCC1 rs25489 polymorphisms and micronucleus frequency (P＞0.05).Conclusion Exposure to lowconcentration benzene may cause chromosome damage in workers exposed to benzene,and the XRCC1 polymorphisms rs 25487 and rs 1799782 may be associated with chromosome damage induced by benzene.