Concerns over escalator safety have been on the minds of many people following the Beijing Line 4 subway accident that killed a boy on July 5. Another accident occurred in Shenzhen the very next week (though it was non-fatal) and reports then surfaced about an earlier accident, also in Shenzhen, from last December. So, is it safe to step back on the moving stairs? Findings from subsequent safety checks – and Weibo – have been less than reassuring.

In safety checks that were initiated after the two incidents in July, The China Daily reports more than 4,000 escalators throughout China have been shut down due to a variety of problems. Meanwhile, nearly 11,900 have been flagged for concern or risk. (That last figure works out to one in 20 Chinese escalators.)

It’s not just the well-worn escalators that are showing problems. Escalators on the Yizhuang Line (currently under construction), the southern subway extension of Line 5, have been recalled for risks of malfunctions similar to the escalator in the Line 4 station accident.

Speculation over what went wrong has blamed everyone from manufacturers to maintenance crews. Beijing’s accident was believed to be caused by a broken bolt – leading many to blame OTIS, the escalator manufacturer. Others are more inclined to hold the subway authorities accountable. The OTIS escalators are light-duty models that are more suitable for shopping malls, rather than high-traffic public transport stations. However, there are no current regulations specifying certain models or standards for public transport escalators.

The lack of maintenance and maintenance crews is also being questioned. Escalators are rarely maintained; the common practice is to call in crews only when something breaks. And the quality of their work can be shoddy, as most maintenance crews are made up of migrant workers with little training.