Construction company Tiong Seng issued a stop work order for two hours last Thursday at the site of a Housing Board development Waterway Terraces.
Company director Derick Pay told reporters that the PSI level was around 400 at noon on Thursday. The company ceased work to protect the health of the over 500 construction workers at the Punggol site.
Mr Pay was speaking to reporters ahead of a visit by Defence Minister Dr Ng Eng Hen, who is also chairman of the haze interagency task force, and Manpower Minister Tan Chuan-Jin.
Tiong Seng has also provided all workers with N95 masks and conducts daily briefings on the haze situation. Mr Pay said the company had already stockpiled some masks before the haze worsened and did not have problems getting more.