We earned an adjusted $1.44 per diluted share for the second quarter.
Adjusted operating income margins for the second quarter were a strong 5.47% [Phonetic].
Operating cash flow is excellent at $276 million on a year-to-date basis.
We accomplished this in an environment where we had 15.5% negative organic revenue growth for the quarter just ended.
Our Mechanical Construction segment performance was exceptional with operating income growth of 24% and 8.5% operating income margins.
Our Electrical Construction segment had strong operating income margins of 7.2%, despite having a 20.17% [Phonetic] decrease in revenues as they were more significantly impacted by the mandated shutdowns than our Mechanical Construction segment was, and further the Electrical Construction segment is more exposed to the volatility caused by our oil and gas exposure in this segment.
Our US Building Services segment had a very strong quarter with 5.6% operating income margins, despite a 9.8% revenue decrease.
We cut executive pay 25% in the quarter, cut other salary employees pay in the quarter, furloughed staff, permanently laid off salary staff, cut almost all travel and entertainment expenses, and reduced any additional discretionary expenses.
We reduced $21 million in the quarter versus the year-ago period, and when removing incremental SG&A for businesses acquired, we cut $28 million on an organic basis.
With all that said, we leave the quarter with a strong RPO position of $4.6 billion [Phonetic], our balance sheet has strengthened through the quarter despite adverse conditions and an even more competitive cost structure than we already had.
Consolidated revenues of $2 billion, were down $310.2 million or 13.3% over quarter two 2019.
Our second quarter results include $50.2 million of revenues attributable to businesses acquired, pertaining to the time that such businesses were not owned by EMCOR in last year's second quarter.
Excluding the impact of businesses acquired, second quarter consolidated revenues decreased approximately $360.4 million or 15.5%.
United States Electrical Construction segment revenues of $445.9 million, decreased $123.5 million or 21.7% from 2019 second quarter.
United States Mechanical Construction segment revenues of $790.4 million, decreased $32.7 million or 4% from quarter two 2019.
Excluding acquisition revenues of $47.9 million, this segment's revenues decreased organically 9.8% quarter-over-quarter.
Second quarter revenues from EMCOR's combined United States Construction business of $1.24 billion, decreased $156.2 million or 11.2%.
United States Building Services quarterly revenues of $472.4 million, decreased $51.3 million or 9.8%.
Excluding acquisition revenues of $2.3 million, this segment's revenues decreased 10.2% from the record results achieved in the second quarter of 2019.
As a result, our Industrial Services segment's second quarter revenues declined $212.2 million from the $295.5 million reported in 2019 second quarter.
This represents a reduction of $83.3 million or 28.2%.
United Kingdom Building Services revenues of $93.1 million, decreased $19.4 million or 17.3% from last year's quarter.
This segment's quarterly revenues were also negatively impacted by $3.4 million of foreign exchange headwinds.
Selling, general and administrative expenses of $205.2 million, represent 10.2% of revenues and reflect a decrease of $21.1 million from quarter two 2019.
SG&A for the second quarter includes approximately $7.2 million of incremental expenses from businesses acquired inclusive of intangible asset amortization, resulting in an organic quarter-over-quarter decrease of approximately $28.3 million.
During the second quarter, we identified certain indicators of impairment within those of our businesses that are highly dependent on the strength of the oil and gas and related industrial markets.
The combination of lower forecasted revenue and profitability along with the higher weighted average cost of capital has resulted in the recognition of $232.8 million non-cash impairment charge during the quarter.
$225.5 million of this charge pertains to a write-off of goodwill associated with our Industrial Services reporting unit, while the remaining $7.3 million relate to the diminution in value of certain trade names and fixed assets within our United States Industrial Services and our United States Electrical Construction segments.
As a result of the non-cash impairment charge just referenced, we are reporting an operating loss for the second quarter of 2020 of $122.6 million, which represents a decrease in absolute dollars of $242.6 million when compared to operating income of $120 million reported in the comparable 2019 period.
On an adjusted basis, excluding the impact of the non-cash impairment loss, our second quarter operating income would have been $110.1 million, which represents a period-over-period decrease of $9.8 million or 8.2%.
For the second quarter of 2020, our non-GAAP operating margin was 5.5% compared to our reported operating margin of 5.2% in the second quarter of 2019, reflecting strong operating conversion within most of our reportable segments.
Our US Electrical Construction Services segment operating income of $32.2 million, decreased $11.6 million from the comparable 2019 period.
Reported operating margin of 7.2%, represents a 50 basis point decline over last year's second quarter.
Second quarter operating income of our US Mechanical Construction Services segment of $66.9 million, represents a $13 million increase from last year's quarter.
Operating margin of 8.5%, improved 190 basis points over the 6.6% operating margin generated in 2019, primarily due to a more favorable revenue mix than in the year-ago quarter.
Our total US Construction business is reporting $99.1 million of operating income and an 8% operating margin.
This performance has improved by $1.4 million and 100 basis points of operating margin from 2019 second quarter.
Operating income for US Building Services is $26.4 million or 5.6% of revenues.
And although reduced by $1.6 million from last year's second quarter, represents a 30 basis point improvement in operating margin.
Our US Industrial Services segment operating income of $3 million, represents a decrease of $13.1 million from last year's second quarter operating income of $16 million.
Operating margin of this segment for the three months ended June 30, 2020 was 1.4% compared to 5.4% for the three months ended June 30, 2019.
UK Building Services operating income of $5.4 million was essentially flat with 2019 second quarter, as foreign exchange headwinds accounted for the modest period-over-period decline.
Operating margin of 5.7%, represents an 80 basis point increase over last year as a result of improved maintenance contract performance as well as the implementation of cost containment measures which resulted in SG&A expense reductions.
Quarter two gross profit of $315.3 million is reduced from 2019 second quarter by $31.1 million or 9%.
Despite this reduction in gross profit dollars, we did experience an improvement in gross profit as a percentage of revenues with the reported gross margin of 15.7%, which is 80 basis points higher than last year's quarter.
We are reporting a loss per diluted share of $1.52 as compared to earnings per diluted share in last year's second quarter of $1.49.
On an adjusted basis, after adding back the impairment loss on goodwill, identifiable intangible assets, and other long-lived assets, non-GAAP diluted earnings per share is $1.44 as compared to the same reported at $1.49 in last year's quarter.
This represents a modest reduction of $0.05 or just over 3%.
Revenues of $4.31 billion, represent a decrease of $169.1 million or 3.8% when compared to revenues of $4.48 billion in the corresponding prior-year period.
Year-to-date gross profit of $648.3 million is lower than the 2019 six-month period by $6.8 million or a modest 1%.
Year-to-date gross margin is 15%, which favorably compares to 2019's year-to-date gross margin of 14.6%.
Selling, general and administrative expenses of $432.2 million for the 2020 six-month period, represent 10% of revenues compared to $432.4 million or 9.6% of revenues in 2019.
We reported a loss per diluted share of $0.14 for the six-month ended June 30, 2020, which compares to diluted earnings per share of $2.77 in the corresponding 2019 period.
Adjusting the results for the current year to exclude the non-cash impairment loss on goodwill, identifiable intangible assets, and other long-lived assets, results in a non-GAAP diluted earnings per share of $2.78.
When comparing this as adjusted number to last year's reported amount of $2.77, we are reporting a $0.01 increase.
I would like to remind everyone on the call that our performance for the first six months of 2019 set records for most financial metrics with earnings per share in particular, exceeding the prior benchmark by almost 30%, not to marginalize the sizable impairment charge taken this year, but the fact that on an adjusted basis, we were able to slightly exceed our previous year record.
As noted on the slide, EMCOR's tax rate for the six months ended June 30, 2020 was 59.4%.
So with that said, at this time, our full-year estimated tax rate is between 58% and 59%.
With strong operating cash flow through June, we have paid down the $200 million revolving credit borrowings outstanding as of March 31, 2020 and our cash on hand has increased to $481.4 million from the approximately $359 million on our year-end 2019 balance sheet.
Goodwill and identifiable intangible assets have decreased since December 31, 2019, largely as a result of the impairment charges previously referenced, in addition intangible assets have decreased as a result of $29.4 million of amortization during the year-to-date period.
EMCOR's debt to capitalization ratio of 13.5%, is essentially flat when compared to our position at 2019's year-end and is reduced from 19.9% at March 31, 2020.
We have just over $1.2 billion of availability under our revolving credit line and anticipate that we will continue to generate positive operating cash flow during the last six months of calendar 2020.
Total RPOs at the end of the second quarter were just about $4.6 billion, up $365 million or 8.6% when compared to the June 2019 level of $4.23 billion.
RPO has also increased $167 million from the first quarter of 2020, reflective of the continued demand as we are seeing for market -- continued demand we are seeing for our services in our markets.
So for the first six months of 2020, total RPOs increased $555 million or 13.8% from December 31.
With all this growth, only $11 million relates to a tuck-in acquisition.
Domestic RPOs have increased $346 million or 8.4% since the year-ago period, driven mainly by our Mechanical Construction segment.
Additionally, both of our Industrial Services and EMCOR UK segments increased RPO level by roughly 15% respectively from June 30, 2019.
On the right side of the page, we have, on 12, we show RPOs by market sector.
Commercial project RPOs comprise our largest sector -- market sector to over 40% of the total.
This is a 19% increase from year-end, spurred by our data center projects.
Other very active markets for us are healthcare, and water and wastewater, with these sectors being up 25% and 49% respectively from year-end 2019.
So now I'm going to close on Pages 13 to 14.
Subject to that main caveat, we are likely going to earn $5 to $5.50 diluted earnings per share this year on an adjusted basis adding back the impact of impairment.
I think revenues will likely be $8.6 billion to $8.7 billion.

Summary:
We earned an adjusted $1.44 per diluted share for the second quarter.
During the second quarter, we identified certain indicators of impairment within those of our businesses that are highly dependent on the strength of the oil and gas and related industrial markets.
We are reporting a loss per diluted share of $1.52 as compared to earnings per diluted share in last year's second quarter of $1.49.
On an adjusted basis, after adding back the impairment loss on goodwill, identifiable intangible assets, and other long-lived assets, non-GAAP diluted earnings per share is $1.44 as compared to the same reported at $1.49 in last year's quarter.
Subject to that main caveat, we are likely going to earn $5 to $5.50 diluted earnings per share this year on an adjusted basis adding back the impact of impairment.
I think revenues will likely be $8.6 billion to $8.7 billion.