NEW YORK (AP) – Aiming to prevent a US version of the recent terror attacks in London, the New York Police Department dispatched its own explosives expert to Great Britain to study the July 7 suicide bombings, officials said.

The department also contacted chemical suppliers and other potential commercial sources for suspected bomb components in the New York city area, asking them to call investigators if they noticed anything suspicious, officials said Monday.

Investigators in London have reportedly speculated that bombers in the July 7 attacks used TATP, or triacetone triperoxide, a highly unstable explosive made from commercially available chemicals such as acid, acetone and peroxide.

Traces of TATP, also used by shoe bomber Richard Reid in his failed 2001 attempt to blow up an airplane, were found in the apartment of Egyptian biochemist Magdy el-Nashar in raids at the northern city of Leeds, home of three of the four suicide bombers.

An NYPD detective with explosives training recently returned to New York “with a detailed analysis of the bomb-making techniques used in London”, said Michael Sheehan, deputy commissioner of counterterrorism at the nation’s largest police department.

The investigator, whose name was not released, regularly examines “bomb methodologies that are used around the world” for a special police unit that monitors businesses that could become inadvertent suppliers for terrorists, Sheehan said.

The department has conducted hundreds of security assessments of businesses around the city, advising them to use more video surveillance, better lighting and more guards, Sheehan said.